Based on First Class, I'd say:
Magneto - ESTJ
Sebastian Shaw - ENTJ
Mystique - ISFP (Ugh. Why did they ruin her? She used to be one of the most badass ISTP female characters of all time.)
Emma Frost - ISTJ
Moira MacTaggert - IXFX
Beast - ISFJ
Angel - XSFP, though I'm leaning E.
Banshee - No idea, he was too 'tarded to type.
Havok - ISTP
Darwin - No idea. Too little screen time.
Azazel - ISTJ
Riptude - Who the fuck knows for this lame dude?