I'd go with #3. I think Mormonism is loosely Christian in the same sense Unitarian-Universalists are.
While Unitarian-Universalism has Christian roots and there are Christian UUs (such as myself) UU is not a Christian religion any longer.
As for Mormonism, whether you consider it Protestant depends upon whether one considers the Restorationist branch of Christianity to be a species of Protestantism or a genus of its own.
I always thought everything that wasn't Orthodox or Catholic was Protestant.
That would be a weird definition of Protestantism
Indeed. To be Protestants, they would at minimum need to believe in the three Solas, which Mormons reject, and probably believe in the triune God as well.
I don't think belief in the Trinity is a uniform among Protestant denominations at all.
Poll
