Aww, this is lovely! Very thorough and very sweet.

While there is a hard case for making it appear that Xander could be gay...
See, I disagree. Through s3, Xander expresses appreciation for lots of guys, and even in s5, he notes how compact and well-muscled Spike is. Moreover, "Phases" is an awesome look into his homopanic when Larry comes out to him, and it gets picked up again in "Earshot". I've always figured Xander was bi at the very least, even if he never *did* anything about it.