Yeah, Gae Bolg is guarenteed to hit, which is why EMIYA used Rho Aias to block it rather than dodging, you literally can't dodge it. The throw "just" is guarenteed to hit, the Thrust reverses causality so it is extra undodgable. Yeah, Ath nGabla kinda ruins any attempt to gang up on Cu, since its purpose is to force a 1v1.
A pain in the ass is all Astolfo could be, since he really doesn't have anything to hurt Cu bar Hippogryph, but Cu can counter that with the Bolg'a throw.