What is an overview of the schools of thought regarding the soteriological status of alien life forms? What is an overview of the various opinions on whether alien life forms are saved and can go to heaven?

I would accept the idea that this has not been substantially discussed as an answer if that is the case. However I have found that there is some opinion on this within the Jehovah's witness community and there is evidence that the Pope would baptise aliens suggesting that the Catholic church must have some view on the matter.
The question is purely hypothetical, and would seem to fall under Paul's admonition in 1 Timothy 1:4 to avoid "...attention to fables..., which cause debates rather than godly edifying, which is in faith."  


As of now--April 12, 2020--there is no evidence of life anywhere else in the universe.  


There is an abundance of astro-biologists and other scientists that insist there "must be" extra-terrestrial life; however, I think intellectual honesty would conclude such a claim is a matter of faith.  
Establishing whether there is alien life will be more difficult than examining whether they can be saved and go to heaven.  

If such life exists; and, if that life is intelligent enough to comprehend the Gospel; and, if we can communicate back and forth with that life within a reasonable amount of time; then, your question will take on greater urgency and significance.