For example, I've heard that they put Joseph Smith above Jesus.
Whether it's true or not depends on how you see it. They believe that Jesus visited America and left a whole new set of scripture here. Smith was suppose to be the prophet to proclaim this scripture. In other words, you could say that Smith supposedly had more up-to-date info.
Also, I've heard they are polytheistic, so...
I don't know where you got this idea...
I need some kind of criteria for what the minimum requirements are to be considered a Christian before I can go down the list and check off all the non-Christians.
You said so yourself. Believe in Christ. They certainly believe in Christ. Otherwise, they wouldn't be knocking on my door trying to convert me.
Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.
He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!