Nuts.
Different opinions lead to different churches only when groups try to force their opinion on others. A few things are necessary for salvation. Holding a particular theory about Christ’s nature or Mary’s place is not among them. Tolerance for other’s opinions and the spirit of debate is all that is necessary to get along. The rest is politics and the use of dogma to political ends. As Jesus said, “Get thee behind me, Satan.”
And you can certainly hold the opinion that the person in the next pew or the church across the street is not a real Christian. But your opinion, the bishop’s opinion, the pope’s opinion or an ecumenical council’s opinion will mean jack on judgement day.
If Christ’s nature is unimportant, then there is no salvation to begin with. Either He is Who He is or Christianity and salvation are simply lies.