I shared a room with a young Mormon gentleman while in military service, but as this was before I received the gospel, I never had any discussion about his faith. I call him a gentleman because he was one in manner, not given to drinking alcohol, smoking, or any common vices that scripture would describe as dissipation. His behavior to the extent that I was aware of it was morally righteous.
I also met a young Mormon missionary, a young lady, who rented a room in my nextdoor neighbor's house. This was after believing the Lord, but again, I had no real discussion with her about her faith though we spent about an hour together clearing snow from my neighbor's driveway. I can't imagine how she served as a missionary without speaking about her faith, but her behavior was reserved and respectful.
I don't know if I've interacted with any Mormons on this site, but I have encountered many Cultic notions contrary to sound and long established doctrine in the forums, all from people who identify as Christian.
In my experience with cultists, all interpret scripture to deny the deity of Christ. What little I've read about "the latter day saints" makes claims that the mormons have a different concept of deity which doesn't exclude the person of Christ, but does redefine deity in such a manner as to diminish the godhead in essence.
https://teamfishhooks.com/the-christian-litmus-test/
The above link is not an exhaustive study of popular cults, but does describe some fundamental theological differences between the major cults and "orthodox " Christianity.
I've met very moral Hindi, very moral Buddhists, very moral Chinese ancestor worshippers, but none of these knew Christ, nor could be considered Christian by any stretch of the imagination.
While scripture advises us not to be joined to unbelievers through marriage, there is nothing that forbids friendly relationships with people not of the faith, except in the instance of those preaching a false gospel and specifically in the context of welcoming them into your home and potentially sharing in their evil deeds. This follows directly from the law of Moses and the prohibition against the abomination that brings desolation to a house.
It is impossible to fulfill the great commission of spreading the gospel and "making disciples of men," without engaging unbelievers in conversations as "we go into all the world" and it's clear that we are to do good to all, but especially to the household of faith.
9 And let us not grow weary while doing good, for in due season we shall reap if we do not lose heart. 10 Therefore, as we have opportunity, let us do good to all, especially to those who are of the household of faith. Galatians 6:9-10
