RG I didn’t mean thst it’s necessary to kill your dad to cast the curse, just that if Rumple is her dad that would complete the symetry.
Plus A&E have been walking a very thin line of incest so far… Gold turning out to be Henry’s grandad, the relationship between Rumpel and Regina after what went on with her mum, Regina marrying the husband of her mother’s rival an last but not least Hook and Emma, I mean first he lust after the woman of the dad and then of the son? So taking it a step further would not surprise me.
None of those are incest. Squicky yes, especially Cora making Regina marry Leopold, Incest no.
The Rumple/Zelena kiss if Rumple was her dad, yes that would be incest because no way is that a father/daughter kiss.