Looks like most of it is covered already, I had wanted to add though, you should try hand feeding him either with your fingers and hold it loose enough he can grab it or with a dropper of some sort. I think letting the pellets sink right next to him will help as well. He really does need to eat.
He doesn't seem too bloated from the pictures so I think you can stop fasting him and get him to eat again so that we can see poop and whatnot.
That's pretty much all I have for now but it looks like you've already got plenty more people more experienced than I at this kind of situation
Good luck to Buzz! I'll keep an eye out here anyway, but good luck to both you!