Is Mahāyāna Mahāparinirvāṇa Sūtra later creation?

I cite here from my older discussion, where I copied&pasted from a website on the MPNS but which possibly does no more exist, didn't check it (but noticed such a remark in a more recent discussion found via google).

(my original compilation should be findable using google on the newsgroup de.soc.weltanschauung.buddhismus beginning at 10.apr.2007)

(...)
Historical Background (2)
There follows a fascinating, informative and thought-provoking
lecture (originally delivered at the University of London, SOAS, in
early spring 2006) by Buddhist scholar and translator, Stephen
Hodge, on the Tibetan version of the Mahaparinirvana Sutra. I here
hand over to Stephen!
[S.Hodge]
(...)
It seems reasonable from the chronological data alone to deduce that
the MPNS was formed during the Úâtavâhana era. The Mahâmegha-sûtra,
which is a precursor to the MPNS itself, mentions a Úâtavâhana king
who was the “restorer of the lineage” and this must be none other
than Gautamîputra Úâtakarn.i (r106- 130 CE),
(...)
Virtually 90% of the remaining text of the MPNS involves this person
as the untiring interlocutor who by his questioning draws out of the
Buddha a wealth of teachings concerning the permanence of the
Buddha, the importance of preserving the authentic Vinaya, the need
to purge the San.gha of miscreant monks, the importance of upholding
and promulgating the MPNS, and most of all the tathâgata-garbha
doctrines. Is it possible that we are hearing the actual voice of a
historical individual , called Sarvasattva-priya-darúana by his
devoted followers, his words transformed into a sûtra format to
ensure the preservation and dissemination of his teachings ?
THE ICCHANTIKAS
(...) help, who are excluded from this message of hope: a group of
people collectively known as the icchantikas - the “extremists”.
In the later strata of the text, the MPNS fulminates stridently
against these people, repeating statements like
“apart from icchantikas, the cause of enlightenment will become
present in everybody”
or
“even those who commit the downfalls or perpetrate the heinous deeds
and those who believe that the generation of the aspiration to
enlightenment to be unnecessary will be established in the cause of
enlightenment - apart from icchantikas who are like death”.
So who were these people that the MPNS calls “virulent serpents” ?
This question is succinctly answered thus - “any person, no matter
whether they are a monk, a nun, a lay-man or lay-woman, who rejects
this sûtra with abusive words, and does not even ask for forgiveness
afterwards, has entered the icchantika path . . . . Those who have
no concern about the
(...)
And make no mistake about this - the fate of the icchantikas is
indeed terrifying, for the sûtra says,
“the cause of enlightenment will not be and cannot possibly be
engendered in icchantikas”,
“they resemble burnt seeds because they have extinguished their
wholesome roots”,
“the icchantika has no seed and there is no possibility of him
having any thought of confessing and begging for forgiveness”.
In other words, the MPNS is quite emphatic in its view that these
icchantikas will never awaken the potential of their
tathâgatagarbha, never achieve liberation and never become Buddhas
throughout all eternity.
CONCLUSION
There is one final twist to the story. As we have seen, the sad-
dharma and the bodhisattvas who uphold it were predicted to
disappear around 220CE, if our calculations are correct. It seems
likely that the MPNS was circulated as the final life- belt for the
sinking raft of the Dharma - those who had ears to hear had this
last opportunity to save themselves. But what then ? No more
authentic Dharma, no more true teachers and no hint here of future
Buddha-saviours to come in this corner of sam.sâra. In fact, there
is this chilling passage in the MPNS:
“Who do not see the goal ? It is the icchantikas who will not see
the goal, for they will not see the goal as long as cyclic existence
lasts. I have summarized and taught the significance of this, but
you should fear what is extremely fearful ! Supposing that all
beings in unison were to become fully awakened to supreme and
perfect enlightenment, then even if it were possible for the sinful
icchantikas to become fully awakened to supreme and perfect
enlightenment, they would not see the goal. In that manner, you, o
hero, should understand things !
“Whose goal does not end in failure ? The Tathâgata's goal does not
end in failure. When all beings who dwell in the cycle of existence
have become fully awakened to supreme and perfect enlightenment,
then the Tathâgata's goal will not have ended in failure and then,
having passed into parinirvân.a eternally, the Buddha will become
impermanent, like the flame of a lamp whose wick has been consumed.”

Hieran anschließend folgt die Einschätzung:

in this world - and eventually in the entire universe. Then, those
who by definition can never be liberated - the icchantikas - will be
left behind to wander lost life-time after lifetime for all
eternity. What a bleak scenario !