Board Thread:General Discussion/@comment-24005739-20140929213952/@comment-24674051-20140930150526

Well, at least it would not be a blood relative, but just one through marriage. Besides, they officially made Belle a relative of Henry at the end of Season 3 when Belle and Gold got married. (Granted, step-Grandma, but you usually don't hear that term.)

So, I suppose that this would be about as good a way as any to have Anna and Elsa related.

Having said that... Just say  No  to more relatives, unless it is a child of Belle, Snow, Regina, or Emma.