What is difference (Vedic) Consciousness versus Pali Text terms "Deathless", "Awakened Awareness"?

OP: Impermanence-- so what is it that is described above as "permanent", "deathless"?
What is it that is referred to as "unfashioned", "exquisite", "bliss", "the ultimate"?

That is Nibbana, and not god or Brahman or any kind of Ultimate Reality. It is that which is experienced by the mind, when it is completely free of all fetters and defilements.

I quote from this answer below. Please see that answer for details.

So, Nibbana is not a thought of the mind, not a concept of the mind, not a state of the mind, not a state of consciousness and also not a feeling. However, when the mind experiences this Nibbana, which is not conditioned, not compounded, not suffering, not impermanent, not arising, not ceasing and not changing, it experiences bliss. The mind can therefore experience Nibbana, but it cannot feel it or think about it.

Sukha or happiness for an unenlightened person is experienced when encountering pleasant feelings (from the six senses) or when encountering the cessation of painful feelings (from the six senses). But for an arahat, sukha or bliss (in this context) is experienced when encountering neutral feelings, no feelings and Nibbana.

Next ...

OP: What is the semantic difference between what is referred to by some traditions as "consciousness" and Buddha's exquisite, permanent "awareness of Awakening"--"without feature or surface, without end, luminous all around" — "lying outside of time and space, experienced when the six sense spheres stop functioning (§54)"

OP: If not consciousness, what is the correct term for "consciousness without feature" that Buddha refers to?

That's Nibbana, and it's not a kind of consciousness.

Bhikkhu Sujato translated part of MN 49 as:

Consciousness that is invisible, infinite, radiant all round—that’s what is not within the scope of experience based on earth, water, fire, air, creatures, gods, the Creator, Brahmā, the gods of streaming radiance, the gods replete with glory, the gods of abundant fruit, the Overlord, and the all.
Viññāṇaṃ anidassanaṃ anantaṃ sabbato pabhaṃ, ...

This translation is problematic because there is no such thing as infinite consciousness in Buddhism. Equating Nirvana with infinite consciousness would be more of Advaita Vedanta rather than Buddhism.

However, in this answer, Bonn explained that this is a wrong translation.

It should rather be:

That which could be known (Nibbana), is invisible, infinite, radiant all round—that’s what is not within the scope of experience based on earth, water, fire, air, creatures, gods, the Creator, Brahmā, the gods of streaming radiance, the gods replete with glory, the gods of abundant fruit, the Overlord, and the all.
Viññāṇaṃ anidassanaṃ anantaṃ sabbato pabhaṃ, ...

So, Nirvana is something knowable, but it is not within the normal scope of physical and mental experience.

OP: How do you describe this this freedom that carries over even when the awakened person returns to ordinary consciousness?

That is Nibbana, and not god or Brahman or any kind of Ultimate Reality. It is that which is experienced by the mind, when it is completely free of all fetters and defilements.

OP: What is difference (Vedic) Consciousness versus Pali Text terms “Deathless”, “Awakened Awareness”?

Please see the second half of this answer.

Nibbana is deathless, because the mental idea of the self is destroyed and with it goes the idea or suffering of death of the self. It's not because the enlightened person becomes an immortal.

"Vedantic teachings inevitably lead to the direct discovery that "consciousness is all."

This is not so for the Buddha. https://suttacentral.net/en/mn1

“Thus have I heard. On one occasion the Blessed One was living in Ukkaṭṭhā in the Subhaga Grove at the root of a royal sāla tree. There he addressed the bhikkhus thus: “Bhikkhus.”—“Venerable sir,” they replied. The Blessed One said this:

Bhikkhus, I shall teach you a discourse on the root of all things. Listen and attend closely to what I shall say.”—“Yes, venerable sir,” the bhikkhus replied. The Blessed One said this:

...

The Arahant (and the Tathagata)

..

He directly knows all as all. Having directly known all as all, he does not conceive himself as all, he does not conceive himself in all, he does not not conceive himself apart from all, he does not conceive all to be ‘mine,’ he does not delight in all. Why is that? Because he has fully understand it, I say.

He directly knows Nibbāna as Nibbāna. Having directly known Nibbāna as Nibbāna, he does not conceive himself as Nibbāna, he does not conceive himself in Nibbāna, he does not not conceive himself apart from Nibbāna, he does not conceive Nibbāna to be ‘mine,’ he does not delight in Nibbāna. Why is that? Because he has fully understand it, I say."

With consciousness, The All, Nibbāna, every thing, the Buddha simply asks each person to treat "This as this, not this as that and that as this." The Buddha denied the usefulness of the law of identity (imo). This seems reasonable, because whatever you choose to 'know', you will only 'perceive to know'. An individual's perceptions always get in the way for identity to be established!

A condition is not an Essential property (at least within Nagarjuna's discussions).. Cause points to an Essential concept, whilst condition is simply an empirical reason to which we can turn to explain why an effect has dependently co-arisen (the effect also being conventional in this case!).

"He (The Buddha)... discovered a reality — the Deathless — that no words could describe."

This is not entirely accurate imo. Look at Nagarjuna's dedicatory verses to the Mulamadhyamakakarika:

"I prostrate to the Perfect Buddha, The best of teachers, who taught that Whatever is dependently [co-]arisen is Unceasing, unborn, Unannihilated, not permanent, Not coming, not going, Without distinction, without identity, And free from conceptual construction."

No mention of the 'reality of the Deathless is stated'. In addition, the Buddha specifically criticized individuals who asked what exactly cessation is (to paraphrase, somewhere in the DN, but can't find it, sorry!), saying that they have 'gone beyond the round of questioning'.

The basic starting point for Hindu philosophy (imo, as I am not as well versed in Hindu theory, going through Samkhya fully atm, read some of Shankara's Advaita..) is that Brahman is 'neti neti', 'not this, not that'. This is just like Nagarjuna's description of dependent co-arising - a negational truth. The difference is that the Darshanas go from there and give positive, Essential, definitions of Brahman and Atman: The real, unlike the unreal that is our empirical experience. But no matter how you spin the above, in that 'real' and 'unreal' are defined, that is only Dvaita!! (Plato's Parmenides shows this within logic imo, but I am only starting to think through this fully, have a look at it, it is very fun! http://plato.stanford.edu/entries/plato-parmenides/ ).

If there is a clear and permanent line that can be drawn between the Atman-Brahman complex and the empirical world (as seems to be the case with Advaita), or between Soul and Nature within Samkhya (sorry, only have translations, not sure if those are Atman and Brahman.. assume so!), you have two, entirely separate, fully independent concepts). Samkhya embraces the Dvaita, whilst Advaita imo lives with a contradiction!

The Buddha never stated that either consciousness, or The All, or even Nibbāna are independent entities that could be considered 'real' relative to the 'unreal' that is the rest.. This is evidenced by the fact that Nibbāna is only achieved by the Noble Eightfold Path! This clearly demonstrates, without any doubt, that the Buddha considered even the experience of the end goal to be dependently co-arisen! (which (I would have to conclude) is also empty in and of itself, but don't quote me on that!)

In fact, if "Truth is One", then all Darshanas have the issue that there is an Ultimate truth that is Brahman/Atman, and there is a conventional truth that is Empirical Experience. The Buddha also stated (somewhere in the Sutta Nipata, sadly no quotes again!) that 'I also teach Truth is One..' (to paraphrase), but that truth was that "every thing that has a beginning, has an end", dependent co-arising and the emptiness that follows from it! With this, there is no dividing line between the Ultimate and the conventional, as Nagarjuna later stated.

To paraphrase Nagarjuna again, if Nibbana was not dependently co-arisen, but an essential, independent quality, what would be the use of a path? Either you had it or you didn't. But if everyone has it, then everyone is enlightened, and suffering/stress remains an unexplained phenomenon.

I'm still thinking about this, but the Kapila Sutra states in book 1 that:

Aph. 67. Since the root has no root, the root (of all) is rootless.

This is not dissimilar from what the Buddha stated in MN 1.. (my current thought is whether this is better phrased as "the root of all things is found empty", or "the root of all things is not determined". I like the first one, but it is a positive description of a thing that cannot have a positive description, if 'neti neti' is stuck to truly!

Also, there is:

Aph. 79. It (the world) is not unreal; because there is no fact contradictory (to its reality), and because it is not the (false) result of depraved causes, (leading to a belief in what ought not to be believed).

Now to me, this is very problematic given recent advances in the interpretations of quantum mechanics ( https://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics ), you have a new, relational ontology, where each individual quanta has no intrinsic qualities.. Relational QM states that all properties arise out of a quanta's interaction with another one. As such, there is no "external reality".. in fact, there is no "external" or "internal" (the Buddha said this once in the Sutta Nipata somewhere, but again, no quote - sorry!), because, like with the Buddha's concept of Anatta, there is simply no ontologically real ground on which to build any notion of essential difference, or similarity, or both, or neither!! ( http://philpapers.org/archive/CAPIOQ-2.PDF )

I would be interested how Hindu philosophers reply to the above issue! (the question would be - if Brahman and Atman are real and identical, what exactly is created within an unreal empirical experience? If 'something in and of itself' stands opposed to 'nothing in and of itself', what exactly has this 'something in and of itself' achieved by creating an illusion? Surely Brahman-Atman can't then be considered the holder of Satya!!)

Now for the questions!

1) "Tao called Tao is not Tao".

2) You have gone beyond the round of questioning!

3) Consciousness without feature is probably best described with silence.. after all, language expresses features.

4) Like Ramana Maharishi, and like Huike did when asked by Bodhidharma:

Bodhidharma asked, “Can each of you say something to demonstrate your understanding?”

Dao Fu stepped forward and said, “It is not bound by words and phrases, nor is it separate from words and phrases. This is the function of the Tao.” Bodhidharma: “You have attained my skin.”

The nun Zong Chi stepped up and said, “It is like a glorious glimpse of the realm of Akshobhya Buddha . Seen once, it need not be seen again.” Bodhidharma; “You have attained my flesh.”

Dao Yu said, “The four elements are all empty. The five skandhas are without actual existence. Not a single dharma can be grasped.” Bodhidharma: “You have attained my bones.”

Finally, Huike came forth, bowed deeply in silence and stood up straight. Bodhidharma said, “You have attained my marrow.”

If Brahman or Nibbana, Atman etc are truly 'neti neti', then all of the Darshans do, in engaging in language, are little more than speculation. Which is why the first Sutta of the Digha Nikaya asks those on the path not to do so! If this is not enough, Nagarjuna in the Mulamadhyamakakarika, explained the Buddha's words within a more philosophical context. His treatise however, is also metaphysics free, in that it never steps beyond the bound of logic and the empirical - neither nihilism nor essentialism are asserted, only the empirically evident dependent co-arising, within the framework of emptiness, is asserted.

5) I am not awakened, so I'm sure someone could say otherwise, but in having given up greed, sensual attachment and aversion, whether the awakened person is conscious or in deep meditation, by the definition of what the end goal is, they are free from attachments. There is not much more than that that needs to be said in this imo!

(in other words, your 5 questions go beyond what language can provide, if you wish to know, find out for yourself! :D )

(sorry, this is a bit long and probably incomplete, but it's a good start imo!)