Unlocking Potential

I'm a bit stumped on who should get the privilege of being upgraded next. The ones with Hearts have good IVs. Some that don't have good IVs Re unmarked and may just have-less optimal IVs. Or set ideas But the following is:
Eliwood: +Attack/-Res
Tharja: +Speed/-Def
Chrom: +Speed/-HP
Jeorge: +Speed/-Defense
Not shown:
3-star M!Robin: +def/-res