No replies on this so far so I'll give it a go... first off, there is not that much information about this - most of mine comes from Pension of the Ancestor Moth and Pocket Guide to the Empire: Cyrodiil.
I always thought that the moth naming of the forts was just based on the ancestor moths, rather than being a sign of a generally moth-obsessed culture. Although of course, we can assume that the presence of the ancestor moth cult, its importance and the fact that it provided exportable ancestor-silk in Cyro-Nordic times would influence the surrounding culture. In that time, the PGE seems to suggest, the moths were just gypsy moths and weren't venerated; that doesn't explain why they would have called it ancestor-silk but maybe it wasn't called that then. In modern times, the Pension says that the silk is still made into clothes as it was then.
The PGE states that "The traditional Nordic pantheon of Eight Divines was replaced by a baroque veneration of ancestor spirits and god-animals, practices encouraged by the mutable-yet-monotheistic doctrines of the Alessian faith. The doctrines eventually codified nearly every aspect of Eastern culture." (I'm guessing from the timeline this is after 1E243? I'm not much good at the history this far back, honestly). This would lay the foundations for an ancestor moth culture, combining both animal worship (of an animal which provided highly prized goods for them in the past) and ancestor worship. The moths are said to carry the fjyron of the ancestor (this is translated in Pension as "will to peace").
By "ancestors" I'm sure they refer to actual human ancestors, not Aedra. This is plausible since we know Dunmer have that kind of ancestor thing going on too and they can definitely summon up ancestor spirits to guard them, so it seems clear that ancestors do have some power.
You mentioned the jills. I don't know too much about Akatosh either, but I looked this up and I think there is something to this. They are said to "mend minutes", and considering the purpose of the Elder Scrolls, it kind of makes sense that this might be obliquely referring to ancestor moths. However, MK himself said that jill is a term for a female dragon, and they would take "suitably draconic forms", so I don't think he had moths in mind.