My CURRENT Avengers Lineup is, new heroes can join but the first Arc isn't going to be like the movie where "SUDDENLY WE NEED AVENGERS

FalCap
Loki [@Bright_Ops] Willing.
SThor - If she comes back to the light side and resolves her Loki issues [@Spud]
Iron Man - [@DrewVonAwesome] willing.

Possibly Valkyrie [@Angel Vicky] though depends how much time she spends with Doom :P

Hulk won't play a part unless in the final fight Loki decides they need the big guns. In temrs of the final fight more people can be drawn into it though may not be officially recognised as Avengers.