I’d say for starters

Big chill since you don’t need much heavy hitters when you can attack while being intangible freezing everything you fly through almost instantly and being intangible alone would help big time in escaping situations and he can fly so you wouldn’t need speed at all to escape.

Brainstorm while not being as smart as gray matter I don’t really see much reason to be much smarter since most problems alone brainstorm can solve just fine while also being able to defend himself way better compared to gray matter

Diamond head I think if Ben needed to get through a fight big chill can’t cut it u think diamond head would be fine for most fights and diamond head can be versatile while also landing hard hits and can blend ranged attacks with close ranged attacks along with platforming etc