I like your first two suggestions. But, again, Rey must be viable for the sake of the plot. Nev’s explanation makes the most sense there.

What I like most about this idea is that it isn’t a complete retcon of TLJ. It’s just a clever way of taking the reveals in that movie, leaving them (mostly) the way they are, and expanding on them. The people she knows as her parents are the most unknown people in the galaxy - probably getting drunk all the time to bide their time. Kylo misinterprets currency being handed between Unkar and them as her being sold, but they instead paid for her to be looked after while they searched for Lor San Tekka. Her vision in TLJ’s mirror cave can’t show her parents because she doesn’t have any. Snoke likely knew her true identity and that’s why he wanted her killed - more competition for himself. And most importantly, it’s a dramatic reveal that is so distinct from merely being a descendant of somebody evil. It stings so much more to be told you, for all intents and purposes, ARE them.