The reasons I put Angel on the list...
1. For a memorial like that, it wouldn't be someone like Nightcrawler. It would have to be someone that had some sort of status. Professor X being a rich man and the leader of the mutants basically...Angel being a very rich man and member of society...
2. If you look at the mansion where Angel supposedly lives, its the place that has the vines and that plantlife. If you look in the background of that scene, you can see that. I doubt if Cyclops were to die, they would put a memorial for him in Angel's front yard or whatever lol.
3. He's Angel...and that's a name of death and of hope and such.
4. Angel does become Archangel at one point. If they're prepping for Apocalypse, he could be brought back to life (though I don't like the idea of bringing someone back to life, again. Which is also why I don't think they'll just kill Jean off again. Kill her to bring her back to kill her? Won't be as effective as the first time.)