...and he's in the clear!  Doc is confident that they got good margins, and they don't anticipate any recurrence.  He'll be getting regular checkups with his regular doctor for a few years to make sure nothing comes back, but the outlook is good.

As for the little man himself, he's moving around well, and I just unblocked the stairs to give him more access to the house.  He's mastered the couch, but my bed is still a bit high for him, so I'll be looking into getting pet stairs for him soon.  He is also happy to be finished with the collar and medicines, and has started trying to make a run for it to go outside anytime I open the door.

Little by little life is going back to normal.