Here is a great article that sums up the "alien" question, it's my take on the matter too. This is written by a BYU professor, is on the LDS.org website and was published in one of the churches magazines back in 1970. That seems pretty mainstream to me. If people don't talk about it much it's because most people don't really care.
I do because I love to look up at the stars and ponder the eternities up there, but for most people life is about more down to earth stuff.
https://www.lds.org/new-era/1971/04/people-on-other-worlds?lang=eng
The Kolob stuff is expanded upon in a reply below in case it can't be seen.