People gota understand the word “muslim” and its basic believes. As long as a person from “any sect” is on those basic believes then it does not matter which sect they belong to .. .. but if those believes are not according to “islam” then for sure he is not muslim and thats the reason that some ulama from some sects put some restriction of marriage and other things on other sects.
Remember, fighting on the things that which sahaba was greater, or who should have been caliph first is not something related to islamic believes. These are never ending arguments similar to different way of offering prayer in different sects. But as long as those sects fullfill the “faraiz” of a “namaz” they are good to go (i mean i would never argue on the thing that why din you do rafa-e-tain or why you did it) .. ..