“Bunny” is often used for a baby rabbit, but it doesn’t have to be. In fact, the word “bunny” is derived from the word “coney” (pronounced “cunny”), which is what rabbits were called until the 18th century. So where did “rabbit” come from? Turns out it used to be the word for a baby hare.
“I hope it’s because they got married and she took his last name, otherwise it implies that they could be family and that’s potentially incest.”
Or maybe it’s one of those situations where there aren’t a lot of surnames? There are real world populations that are way more diverse than their distribution of surnames might imply.