We just got back from the vet's office. Tucker checked out pretty well. He lost about 1.25 pounds, which is actually less than I'd guessed. He did not have external parasites or any injuries. We were not able to get or bring a stool sample (he has not pooped yet), but I can always drop one off later this week.
We had bloodwork done and it came back good! No problems with his kidneys and no infections.
We had already scheduled a check up in early December, but the doc said we didn't have to bring him back for that.
Tucker, you are a fortunate boy!