[Galin]

I'll probably add something on the question of whether or not the author of DA misrepresented the teaching of the Elves, but for now I'll just add that Christopher Tolkien seems to think the idea was (vaguely enough) men of a later time -- but I note the second quote too:

'Where could such ignorance of the Elves be found but in the minds of men of a later time? This I believe, is what my father was concerned to portray: a tradition of Men, through long ages become dim and confused.'

'(...) I conclude therefore that the marked differences in the preliminary sketches reflect my father's shifting ideas of what the 'Mannish tradition' might be, and how to present it: he was sketching rapidly possible modes in which the memory, and the forgetfulness, of Men in Middle-earth, descendants of the Exiles of Numenor, might have transformed their earlier history.'

Christopher Tolkien, commentary, The Drowning of Anadune, Sauron Defeated

'Descendants of the Exiles of Numenor' is interesting here.

Aiwendil wrote: The other possibility - which I find most likely - is that the reference to a 'mixed tradition' does not imply that the Akallabeth was actually intended to have compiled from an Elvish text and a Mannish text. Rather, this text, written by Elendil not long after the downfall, was not compiled from other sources but was written out by him ab initio - but that it naturally drew both on Elvish lore acquired by the Numenoreans and on Mannish lore brought into Numenor by the Edain; and DA was an account written elsewhere, by other Men in other circumstances, but drawing ultimately on the same old Mannish lore. The problem with this is that if the text of DA that we have is considered the 'real' text, then it clearly does have a shared textual history with the Akallabeth, since there are such strong similarities of wording.

Maybe Elendil wrote AK, drawing upon two traditions in general as you say -- and much later, oral versions based on Elendil's tale became simplified and confused, but retained similarities of wording to Elendil's account; and one of these versions is written down as DA.

Maybe?