It dawned on me, reading this, how different the dynamic between Buffy & Faith is here vs canon. (Yeah, I'm slow.)
In addition to the changes Buffy has been through during her summer with Spike, B & F's relationship is so much more developed and is without the particular angst of that rabid jealousy Buffy felt over Angel's seeming attraction toward Faith.
Even if Angel does show up in this S3-AU timeline, that angst won't be there, and I have enough confidence that Spike won't pay any heed to attentions that Faith might toss his way.
Mostly, I'm just desperately glad that Buffy now has someone she can *talk* with about this, rather than just bouncing things around in her own head, or flinging words against Spike.