XMenFilms.net has provided us with a possible update on the X-Men 3 casting and characters:
I just got some new word on X3. Gambit and Beast we can confirm. Not sure about Angel. Hugh, Famke, Ian, and Patrick are back as of today. This is in addition to the actors already optioned for X3.
Anna, Halle, and James are NOT signed yet, though by the end of the week, they should know what will happen with Anna Paquin.
Looks like besides Phoenix, the SENTINELS are in, including a character called Dr. Bolivar Trask.
Source: XMenFilms.net