Interesting progression of the story - keep it up!
I know I'm a bit late to this but I'd like to say ‘well done’. That's really nicely written.
It's not exactly my thing – too straight m/f and a bit too vanilla, even if there is a light touch kink element to it. But I love the story you're telling with the developed back-story – love the sense that there's a big multi-pairing, sexually fluid interaction in the background with Harmony/Cordelia a thing and all the various couplings in Xander's backstory and then there's the whole who-fucks-who HP arc (though I did want to know who Hermione is with – hopefully a nice girl) which I thought was very neat.
Also think you've got a nice voice for all your characters. I can hear some of that dialogue - and I love dialogue.
I know it's been a while but I really hope you write the other chapter. Maybe end it with a call to Cordy! And maybe you can spin off what’s the deal with Tara, Faith, Rhona, Willow and Buffy...
Either way – nice work. Thanks.