Yes, generally the game tries to keep close family members together (except when kidnapped or busy working as a noble/merc somewhere else) so I guess it makes sense it would pull in relatives of the hostile/not-hostile priests.
Well...the holy courtesy that Fishy want's to leave with isn't the "hostile" one on the map -- at least there are two different names and job-color classifications: Fishy's holy courtesy has a farmer-brown color while the "hostile" is noble purple. And the one that Fishy wants to take with him isn't on the map.
Uh-oh...Fishy's wife, who immigrated with him, is the niece of the baron consort who's hanging around my reclaimed tavern. And by the way, the dwarves who used to own this place before the forgotten beast showed up and wrecked the joint must have really known how to party: My tavern was jumpin' with a dancer, bard, two poets, a baron consort, and a spearman of all species before I was half-way unpacked. And some friends they turned out to be -- not one even lifted a finger to help my dwarves move in. Good thing I didn't embark with a fridge, 'cos otherwise I'd have to run an extension cord all the way down to the magma sea.
Turns out that Fishy is related to about a billion dwarves: He's got nine-pages of relatives, the missing holy courtesy is his only daughter, and he's probably related to Pope Francis through two degrees of separation. I guess he's staying. Let's hope he doesn't bring all his family because my computer can't handle more than thirty dwarves, and I'd hate to have to delete his universe because of his familial fecundity.
Thanks again, everybody!