First off, the relevant trait:

TRAITOR TO ALL: As you reveal your force, you may choose that Noh-Varr loses all keywords this game. If you do, modify his attack value by +1 this game.

So, suppose you've equipped Noh-Varr with the Dark Avengers ATA.

1) Can he still use his Trait?
I expect the answer is "yes," as there is nothing to prevent it.

2) If so, does he lose the Dark Avengers ATA?
I expect the answer is "yes," since he no longer has the keyword.

3) What happens to those four points?
I expect the answer is that is "the four points remain attached to Noh-Varr," just as if Disbanded were in play.

Are these expectations correct?

Thanks!

-J

i'd agree with all your pooints, the ATA was assigned, its just that he no longer meets the pre-req, so its not given to the opponent until he is KO'ed

Sounds right.