It's ridiculous to combine Islam with Christianity
Islam still works in the mindset of Judaism, that only a few set of prophets get revelation from God. Back then God dwelled among men.
Yet the last of those line of prophets ended with John The Baptist. It ended there!!! no muhammed's or joseph smiths or anyone can change that.
Ever since then due to the holy spirit that went out, God dwelled IN us. Ever since then, Truth is aware in all of us it only need's to be accepted, this part of the triune nature of God isn't teached in Islam, and is totally rejected in Islam. The main reason this is, is because it's an 80% jewish religion... islam took all the jewish standpoints concerning jesus.
That he wasn't the son of God, That he wasn't crucified, that God doesn't have a triune nature, etc...
Muhammed loved the jews (or there wealth), and wanted to be one of the great prophets of israel... and persecuted the jews when they didn't accept him. It's for this reason that he first asked his followers to pray towards jerusalem, he was seeking acceptance. Too bad that in order to be a jewish prophet he had to be accepted by the sandrehenin, had to be of jewish lineage, must of agreed with the previous revelations and must had prophecies or miracles in his name. Muhammed had none of them.
Muhammed isn't a prophet, just a caravan raider with big imagination who conquered far and wide... that's not the first time that it happens with conquerers, hitler thought he was doing God's work too, Ghengis Kahn thought he was God, The Ceasar's of rome were to be worshipped as God, and so on and so on...