See the point, but Utah is a worse location strategically speaking. Completely throwing them out of North American a la the Spanish Empire's deportation of Jews and Moslems is not really an option in the twentieth century. They have to be moved within the continentI dunno, deporting anI-American Mormons to anti-American Canada seems like a bad mixture.
There is no non Canadian island that is suitable and sending them to say the Great State of Houston would put them too close to the CSA.
Onreflextion within Canada, southern Manitoba is out . Instead I would look at say northern Alberta or the Newfoundland coast. A place with a low Canuck population, a fair distance from the USA and with unpleasant weather. Remember, TL_191 USA did not have much against Canadians but they really hated the CSA and Mormons.
Given that it was not done in the second trilogy I don't think that a nasty enough president was elected so this is all theoretical so to speak.
Declaimer: I wish to state that in the real world I do not believe in deporting people just because they are politically inconvenient.