Hi Mal! I have def experienced the Too Many Characters problem (though not for a long time) so I sympathize!
I will be real and say that I'm not familiar with the canons for most of yours, but they all sound cool! And Irene will def relate to being frustrated to be here, and I think she'll maybe be drawn to Barbara? Still waiting to see how she responds to all the magic stuff, though I think the mutants in particular might freak her out a little >>
NEBULA. Endgame broke my heart in many ways, but I was glad to see more of Nebula. She's great. And as I said to someone above, Irene's good with morally ambiguous types so I think they might get along.