Remembered this forum and wanted to pop in and give an update. Buddy is still doing great. As time went along, he began to show some of the more persnickety behavioral traits of some Basenji's . . . independent, aloof, tough to train sometimes.
He's still not fond of thunder, but doesn't tremble like he used to. He's about 90% on recall, though usually puts his own spin on it ("Buddy come" . . . looks at me, stalls for a second, then trots over).
He never chewed on anything, never peed on anything, no separation anxiety.
All in all, very happy with him, and he seems pretty happy with me. My very alpha cat (cody) passed a few months ago and buddy didn't even really seem to notice much, but I took the opportunity to spend some extra time with him and give him some extra treats. He naturally enjoyed that.
Hope y'all are doing well, and thanks again for the help.