Havok was obvious but def not Psylocke (especially since FA hasn't been cancelled). Most people thought she was Spiral/Rasputin/Deathstrike.
Wolfsbane isn't getting a push, so having her on two books is really unlikely. I think that's actually Penance now. Her claws seemed chubbier where Penance has longer claws but that might just be the angle.
Mr. Sinister is def in this and I think Marrow might be the one that looks ike the Night King.
Nanny and OM are total curveballs, so I think this might be a 6 issues mini series.