If we import a question from TeX.SX which doesn't have an answer there and give an answer here, do we let the OPs of such questions know there is an answer, but just not on TeX.SX?
Point in question: https://topanswers.xyz/tex?q=362 and its original https://tex.stackexchange.com/questions/518333
Of course this is only applicable once we go public.
I agree with @Caleb that in the current climate posting links on tex.se might not be well received.
While it won't be enforcible for all possible licenses, I suggest to first ask the original author before reposting answers from here on tex.se. For example I would prefer if my answers would not be reposted there.
This is going to be a tricky issue, and will possibly evolve over time. For starters, playing it safe and not stepping on toes is probably the best plan.
Where ever possible, answer questions that were asked on SE on SE. For cases where that isn't feasible (e.g. poster doesn't have an SE account), somebody else is free to post a summary of what was posted here (under CC-BY-SA usage) that does answer the question, but since citing the source is required, it is quite fair to link back to the full answer here.
Also for now...
I think *commenting* on SE with "this question answered [here]" is a bad idea. Either answer the question there or don't. The primary source material can be posted here first, but either answer posts or don't, just linking without answering will only fuel animosity.