I've been trying to figure this out for a huge Goth family tree I want to do in sims 3. I have no concrete proof so I kind of just decided that Simon (Agnes & Cornelia's dad) is the son of one of them. In my mind, Belinda is his mother since I think they're the most alike. I also think another sister has a child who eventually has Agatha Crumplebottom, Agnes' distant cousin from Cottage Living. I also found out some other descendants in the Mysims series, Mrs. Crumplebottom's niece Elvira Clamp & Elvira's nephew Ian Arneson. If you find any other random Crumplebottoms let me know for the family tree 👍
