I have already read this.
However I want to know if it is okay to ask a question such as "What references to something exists in ancient literature, folklore, mythology?"
Would that be acceptable here?
Assuming something is a historical person/place/thing, that seems reasonable. Examining references to events in ancient sources is essentially what historians do.
Now if something is a fictional construction, it might be a bit more problematic (and there might be better stacks for the question too).