Well, as happens from time to time, sadly, he was returned to the rescue. His family was being transferred to Hawaii. Turns out that state has a miserable quarantine process to bring domestic animals in and he would have had to be kenneled for about 6 months - regardless of paperwork or anything else. His family couldn't do that to him, so he came back.
He is currently in the "zen" room at the rescue which has a door and is a place for cats to come in that is a little quieter and protected from the open space of the general population at the adoption center.