I personally would say that Ariete is best with 2 copies because her downside is she locks grimoires for 5 turns on open (so you can really only pack 2-3 grimoires efficiently), however on the plus side she can get grims that you used back. A 2 copy required in my opinion. Powerful soul though so you can get for that.
Ainhazard 2nd copy would probably be great if you got the other cards for beltorat kingdom.
Zu has a decent soul and works okay with 1 copy. But yeah, I don't have much experience with big lawt...
Elgandi is...difficult to recommend because he's hard to use and probably requires cards you dont have. Also probably requires 3 copies
Ainhazard (if you got the cards for belt kingdom) -> zu -> ariete -> elgandi