Sundew family

So I noticed in the fishing episode in season one that HP and Sylvia sundew are dating, Sylvia is the grandmother of ivy sundew, sprigs girlfriend, so, there is some problems, le fact that ivy and here grandmother are dating the same family means incestry soo… I know that frogs can I breed, but in that socity of wartwood, I don’t believe incest is ok

TL:DR:

There is incest between the sundew and plantar family’s with gen z and 2 gens back

So you know how Ivy's dad is never shown or Maddie's Mum, why do you think they aren't shown? Is it possible the herrings ate them or that they disappeared on a snow day? Maybe the went to get milk perhaps!