As to Beck being a Mormon, IIRC, when he was dating his wife they didn’t go to any church. She’s Italian, so I imagine she was from a Catholic background as well. They went “church shopping” and ended up in the Mormon church. One of Glenn’s daughters really liked the Mormon church and that’s why they attended it more than once, then they were impressed with the people in the church, and it was Glenn who made the decision to stay.
There’s a couple interviews on youtube where he talks about how he became a Mormon. Search Glenn Beck and Mormon and you’ll come up with the interview (I think they were taped in Utah.)
I guess the theology made not much of an impact.