Jean Grey always has the Phoenix unless the thread creator says otherwise. You can't really even have a forum debate without it because all of her feats stem from her secondary mutation making her ONE with the Force. You could say "classic" Jean but her only Phoenix-less feats are from very very very early X-books in which was was so incompetent she could barely move a book if she tried.
You also specified prep time, so the X-Men will definitely start with shields up lol.
This wasn't evil Supergirl. This was a couple years back. When she took on Wonder Girl and then the other Titans briefly.