Lesbian subtext aside, I really, really love Jubilee and Laura as a team. They need to team up again. As often as possible.
Julie would make a great Avenger. She had one of my favourite moments in Avengers Academy: Her reaction to being stabbed is, "And now I have a knife." That is just such a badass moment and line. Also, she and Karolina do make a pretty adorable couple.
Like vaf, I'm sceptical of taking well-established characters with long histories of heterosexual relationships and outing them. I know that, as far as the Internet is concerned, pretty much every single character is secretly gay. But the risk with outing a character with a lot of history is that it comes across as a stunt, and that might just turn people off it. Even people who actually do want more LGBT representation in comics may just roll their eyes at it.
It would probably be better to go with characters who have already been very strongly hinted as being LGBT. The subtext between Storm and Yukio was always blatant, so at this point, revealing her to be pansexual wouldn't actually be a surprise to anyone, it would simply be confirming something that everyone already knows. Same with Mystique - who it's long past time was actually shown to be bisexual, rather than just "bisexual but only ever sleeps or flirts with men, aside from one woman who died 25 years ago." (Also, let's have a mini about Mystique and Destiny when they were young. Let's see them meet and fall in love and raise some hell.) Same with Hercules, too.
There are major characters who can be outed easily, without it actually being a twist. I'm not really sure that applies to Iceman. Outing him would end up feeling like a big twist, a surprising reveal that the average reader wouldn't have predicted.
Besides, why would you want Iceman to be gay? The guy's boring. He has all the personality of drywall. There are way more interesting characters who could be gay.