My belief is that anyone who believes that Jesus Christ is the Son of God and that he died for our sins is a Christian. I believed that was what made a Christian when I was Catholic. I believe it now.
Even mainstream Christianity can't agree amongst the different sects what makes for a "real Christian" a lot of times.
Do you see the same similarities in Joseph Smith as I do in Mohammad. Both claim personal visitation by angels who dictated the "complete" truth to them...both had multiple wives, some under the age of 15. Both believed in afterlives and history not supported by either Scripture or science...and, ironically, both Islam and LDS sects split into factions after succession questions of whom was given the authority to succeed Smith and Mohammad. And while they both claim to be tolerant of other "people of the book" these religions are very dictatorial in that they do not allow return after excommunication for being involved with other religions nor do they allow even "free agency" questioning and followers who do are severely punished--just ask Salamin Rushdie and Fawn Brodie