Shouldn't Raven be Apple's step-aunt?

I kind a of always had a similar to how marriages work in EAH. I mean if they have to follow their parents the exact way it happened including marrying the sons or daughters of the other side of their family;Isn't that incest? Aren't Apple and charming twins or something? This kind of thing has been bugging me for quite awhile even though it's just a nitpick.Especially since Daring and Apple do in fact look a little too similar for my liking.

ya um raven queen is actually apple whites aunt because if u think back ravens dad is snow whites dad so she is snow whites half sister which makes her apples aunt

This had me really confused, but the truth of the matter is we don’t know how many generations apple white is to the original snow white, so we don’t exactly know how close relation apple and raven are per say. I did google it and it said they had gone down so many generations so it’s hard to say they are exactly related, but again i’m really not too sure.