These are separate, mutually exclusive scenarios. What are the effects of each?
Technically, the very idea of an alternate Mormonism is actually an insult to Mormonism. But that is not intended.
Alternate concept 1: The Native Americans are culturally descended from the Nephites, but racially descended from the Lamanites. Their faith has degraded but they can be converted. They may be more 'noble' at heart than Europeans.
Alternate concept 2: Darkness was only bad in the context of the Lamanites. All Old World peoples are equal if they are Christian. Basically blacks are tolerated in the early church.
Alternate concept 3: Actually many different concepts. Joseph Smith preaches an entirely different religion. Entirely different and not even Mormonism, the reason it's here is because it would still be created at around the same time and in the same place. Called hedonist by many, it allows alcohol and debauchery. Plural marriage is called a divine commandment, but it is also acknowledged to be for pleasure. There's also a message of peace and love. Meanwhile, the OTL Mormon aspects that fit within this mold still occur.
Alternate concept 4: Joseph Smith claims to be Jesus reincarnate.
Alternate concept 5: Wine and rum are permissible, beer is not.