What's the consensus? If you're building a Banshee or other non-human Infected, do you have to pay the BP for metatype in addition to the BP for the Infected Quality?

As I read it, yes.

Else Troll Ghouls FTW!!!!!!!

I also notice that the canon will skew PC Infected to Adepts. In Vampires and Banshees, at least, you're already going to buy up your Magic to enhance your critter powers. For 5 BP more, you can invest those same Magic points in Adept powers, too.

certainly explains why many of the infected are mythically capable of doing some quite inhuman things.

Most racial options that grant you a magic score work best with some awakened quality. Upping your magic score to improve your regeneration ability(or what have you) is good, getting that increase plus more adept PP or a better magic score for conjuring/sorcery is awesome.