I created 2 tin greatswords, one with a framed blade, and one with the kitana blade. the kitana blade sold for almost 200 copper more. I know prices vary, but do the different item variations affect the price it will be sold for?

also how about gold grips, hero guards and round guards?

You can click on a sale to view why you got that much (most likely a patron bonus) guards don't really matter unless the person is asking for a specific one. The skins of the weapon don't change the price either unless requested by the customer