Does sottapana have perfect morality (sila)?

Since a Sotapanna does not have perfect mindfulness & wisdom, it is impossible a Sotapanna has perfect morality. However, a Sotapanna has intimate deep insight into the nature of craving & attachment, therefore a Sotapanna fully abides by the precepts via wisdom but may occasionally lapse in relation to trifling deeds, such as killing a mosquito or lacking perfect speech suitable for each situation.

buddha summed in jaggikāvasathasutta, which you require (but still no translated version in enlish, why?):

sujātā ānanda upāsikā kālakatā tiṇṇaṃ saññojanānaṃ parikkhayā sotāpannā avinipātadhammā niyatā sambodhiparāyanā.

Ānanda, dead Sujātā-upāsikā already ceased 3 saṃyojana (sakkāya-diṭṭhi, vicikicchā, sīla-bataparāmāsa), she is sotāpanna, would not fall from sotāpanna state, and is sure of enlightenment (higher level) in the future.

The translation trick:

Pāli translation (by saṃyojana context's sequence) of first 3 saṃyojana that are destroyed by sotāpanna should be:

Micchādiṭṭhi causes vicikicchā and sīlabataparāmāsa.

The explanation:

Misunderstanding the relativity (causes and effects) causes doubting the relativity and causes doing wrong physical verbal&bodily actions (kāya&vacī-viññatti-cittajarūpa) that cause low-quality resultant-minds&kammaja-rūpa, such as hell realm, etc.

The relativity in buddhism is paṭiccasamuppāda (the dependent origination). Micchādiṭṭhi is in every passion step (avijjā, taṇhā, upādāna) of paṭiccasamuppāda, see the reference sutta the the end of this answer.

The example:

While a child who can do multiplication and addition but he understand only the additive rule of the mathematics. When he receive problem test sheet "3+3x3" and he misunderstood "I can do", then he write the wrong answer "18" because he wrongly thought '(3+3)x3' but it must be '3+(3x3)'. He may doubt "should I multiply first or add first?". In the end, the teacher gave him fail for that answer.

You can see that whole misunderstood, wrong answer, wrongly thought, doubt, and fail come from Misunderstanding the relativity.

The reference:

In samanupassanāsutta showed avijjā-upādāna co-nascently cause (sahajāta-paccaya) diṭṭhi-upādāna (diṭṭhupādāna, sīlabatupādāna, attavādupādāna), taṇhā, vedanā, phassa, etc. So, this sutta showed micchādiṭṭhi is in every passion step of paṭiccasamuppāda (the dependent origination):

(sakkāya-diṭṭhi-upādāna:)‘Intentions from self, or an intending self, or in self intentions, or in intentions self.’ Reflect.

...

The ordinary person touched (phassa) by ignorance (avijjā-upādāna) and feeling (vedanā) in accordance, it occurs to him ‘I be (by bhava-taṇhā)’, or ‘This is my (by upādāna) self (maybe by attavāda),’ or ‘I will be,’ or ‘I will not be (by vibhava-taṇhā),’ or ‘I will be material,’ or ‘I will be immaterial,’ or ‘I will be perceptive,’ or ‘I will be not perceptive (saññā),’ or ‘I will be neither perceptive nor non-perceptive.’

(Above quote paragraph included diṭṭhupādāna, sīlabatupādāna, and attavādupādāna automatically, because of previous quote which appear before this quote in the same sutta. So buddha use "the ordinary person" instead of "ariyasāvako". But in the other paṭiccasamuppāda sutta maybe not auto include those 3 upādāna, because the buddha may taught to sotāpanna-ariyasāvaka, or above, who perfectly and completely ceased those 3 upādāna.)

So, you can see whole dhamma which I quoted above in 1st-3rd pañcaverabhayasutta:

I

2. The householder Anāthapiṇḍika (sotāpanna) approached the Blessed One, worshipped and sat on a side.

...

3. “Householder, when the five dreadful fears are appeased and if you are endowed with the four factors of one who has entered the stream (sotāpanna) of the Teaching and if you wisely see and penetrate the right path, if you desire, could declare, ‘I have destroyed births in hells, in animal wombs, in the sphere of ghosts and birth in loss, evil states and in decrease. I have entered the stream of the Teaching, would not fall from there and am sure of enlightenment (higher level) in the future.’

...

5. “Householder, a destroyer of living things is in fear of having destroyed living things in this life and he dreads and fears the next and experiences mental unpleasantness and displeasure. Someone abstaining from destroying living things is appeased from this dread and fear.

... one who has taken the not given ... one misbehaving sexually ... one telling lies ... one taking intoxicating drink... (5 sīla)

II

11. “Here householder, the noble disciple has unwavering faith in the Blessed One ... the Blessed One’s Teaching ... The disciple monks ... perfect virtues desired by the noble ones... (vicikiccha-saṃyojana cessation)

III

... the noble disciple wisely considers this same depandent origination (paṭiccasamuppāda)...

17. “Such as on account of ignorance arise determinations...

So, buddha summed in jaggikāvasathasutta, which you require (but still no translated version in enlish, why?):

sujātā ānanda upāsikā kālakatā tiṇṇaṃ saññojanānaṃ parikkhayā sotāpannā avinipātadhammā niyatā sambodhiparāyanā.

Ānanda, dead Sujātā-upāsikā already ceased 3 saṃyojana (sakkāya-diṭṭhi, vicikicchā, sīla-bataparāmāsa), she is sotāpanna, would not fall from sotāpanna state, and is sure of enlightenment (higher level) in the future.

It is correct that a stream-winner will not not break the five precepts. On the other hand, that is not one and the same as perfect morality.

As an example, from Mahasi Sayadaw's Manual of Insight:

Out of the ten "wrongs," wrong view, false speech, wrong action and wrong livelihood are abandoned by the first path. Wrong thought, slanderous speech and harash speech are abandoned by the third path.

IMHO introducing the abstraction of "virtues pleasing to Noble Ones" to me seems to be intended to avoid enumeration and getting into explaining how his sila actually works.

In example there is a difference between states that will arise for a lay and monstatic sotapanna, Cula-Sotapanna is different from Normal Sotapanna, Solitary Sotapanna will not have the same Range of Potential experiences compared to a Sotapanna who lives with others, as the sense of respect for the robe or a cultivated sense of shame out of respect for the teacher would be instilled more in the former, a Sotapanna surrounded by the Sangha will lead a different life than a Sotapanna surrounded by Wrong View Ordinary Folk, a Sotapanna with Strong Faculties will make different decisions one with weaker, a combination of these and other factors (latent defilement etc) make one up ones behavior.

In a similar fashion The Aggregates and States of Consciousness which delineate into mental, verbal and physical action are explained in more detail when we look to Abhidhamma and Teachings on the nature of experience and Behavior in general and in Regards to the state of a Sotapanna n particular.

What is impossible is also stated in the Impossible Sutta where the things a Sotapanna cannot do are listed, there is also a list that comes with The Ratana Sutta, Them not killing or wanting others to get killed is from Dhammapada, this is what ive seen in the Canon, Sutta Pitaka and the Abhidhamma.

It is stated in the Sutta Pitaka (Sutta called Recital is at least one instance), where it is stated "Five impossibles, to wit, for an Arahant intentionally to take life, or to take what is not given, so as to amount to theft, or to commit sexual offences, or to lie deliberately, or to spend stored up treasures in worldly enjoyments, as in the days before he left the world."

This was never said about a Sotapanna.

The argument for them being unable to break the 5 precept is based on the verses saying "when a Sotapanna has "eliminated/stilled/calmed(common translations)" the five fearful animosities and easily attains the 4 rupa jhanas then he can be proclaim himself to be a Stream Winner. In those verses it is not said that one becomes a sotapanna when one does not break precepts. It says that "when these have been stilled/eliminated in one (presumably he already is, that is the most face up logical interpretation), it is also not specified if it is dealing with a Sotapanna who knows the Cessation or the Cula-Sotapanna, it seems natural to assume that it means both if anything (but this is a different topic). There is also an ambiguous statement in the Buddhagosa s Visuddhimagga that kind of implies that they can do no wrong action.

Venerable Mahasi Sayadaw was also convinced that a Sotapanna would not break the 5 precepts. Venerable Ladi Sayadaw afaik said he was not sure but leaned towards agreeing with Mahasi Sayadaw.

Ven. Nanavira was raising criticism against the view of Perfect Sila in his time, so it has been criticised for at least some decades and as far as i am concerned the view was never properly defended and is held as orthodoxy by quite a few.

I also have the impression that some Famous Ajahns could be capitalizing on keeping the five precepts and teaching that the Sotapannas dont break the five precepts, because that actually implies that a monastic sotapanna could get involved in some shady stuff outside of the 5 precepts for example and still be perceived as a Saint by layity. It is easier to keep 5 precepts for some people than to become enlightened id assume.

The view i think could also be formed if there was like a Streak of very sober Sotapannas for some time and a view that all Sotapannas are like that couldve formed. These are my thoughts on it fwiw.

A few things other things whch set them apart from Ordinary Folk are that they can do wrong action knowing it as bad with right view and cant do wrong action and hold wrong view about it, they can restrain themselves on account of Right View, there is no such possibility for an ordnary person. So rather than speculating about what they cant do one should focus on that view thing that they got imho.

No, just an Arahat has such. But a Streamwinner has what is called "virtue pleasing and praised by the wise". Not capable to make grave faults and lead deliberate misconduct. In affect he/she is still able to conduct unskillful deeds, but would not hide it and leave them covered, would confess them quick, be ashamed and intent to correct.

(You may find the wish after resources, there where you lead the discussion and try to argue on other place.)

[Note: This is a gift of Dhamma, not meant for commercial use or other lower wordily gains by ways of exchange or trade]