I am keen on the idea of Alex just rocking up to this Fashion Week party. If Tuck has no interest in going (Alex doesn't really, but he wants to torture Beau a bit) then he will likely see Blair and Portia there safely, be charmingly awful and then leave.
I can't decide whether it will be better if Beau knows they are in town, or not. Being forwarned will build up his levels of distress, but there is also appeal in the shock factor of their sudden appearance. Either way, Alex *must* see glittery Beau.
Antoine & Alex
These two will clearly meet at some point. If not this week, than definitely the next?