From what I've gathered online, Xander is doing very well for himself - he's moved up in the company and he's the foreman now who is organizing the crew working at the school.
I, too, believe that Hally was refering to the fact that she was Anya's last friend, and therefore only one at the impromptu 'intervention'.
As for the shifting monster ... I thought it was pretty neat. I also thought it was neat that not only did it take their appearance, it also took their voice, their manners, and their personality/goals. Joss & Crew are smart: If it had been just a shapeshifter, the voice would have remained the same (remember how well SMG and ED were directed, and acted, when their characters switched bodies? Their verbal dynamics and mannerisms changed completely ... it was wonderful), but these were almost identical replications of all of the villains. Veeeeeeeeeery interesting. My guts going "First Evil" on me, too.
And ... since I've been busy at school, I haven't done any spoiler hunting for anything beyond the first few eppies. *hyperventalating* I'm going to go ... *gulp* Spoiler Free this year!!!! EEK!