So, your party is as follows:
The worst possible build for a druid is to focus on summoning, so you need to actually CARRY another tier 1 character
bard who NEEDS to prestige to make his build viable (too many things later on are immune to mind-affecting), so hopefully he makes the right choice(s)
cleric of ilmater doesn't really need to prestige, nor be a persistabuffer, but I(we) suggest that you help him be a persistabuffer as it is a very good build from level 1
binder (don't know much about "BSF" or binders in general, so can't really give opinion)
you the wizard
Three tier 1 characters in a party should allow you guys to succeed at everything. The only issues you might run into are poor choices for the other tier 1's, a bard who doesn't prestige into bardic-music PRC's, and a binder who looks cool on paper but doesn't really contribute much to encounters and non-combat play.
So, you need to be able to carry the party. Not that hard to do as a wizard, but you might get tired of being the only person winning combats (or might not
)
Domain Wizard 5 / Incantatrix 10 / Wizard +5 (don't do Archmage, IMO it's a waste of feats), once you are 20th, just advance Incantatrix to infinity, no need to pick another class.