Okay, let's get really confused. Joe Haskell was a cousin to the Jennings twins (and Amy). There are a coupla ways that woulda been possible. First, Joe would have to be descended from one of the 1890's Collinses other than Quentin. That would seem highly unlikely. Second, he would also hafta have been descended from Quentin. Quentin's daughter was Lenore; she had a daughter who was the mommy of the Jennings. But Lenore could've had other kids as well, maybe another daughter who married a Haskell. But then why wasn't Joe a werewolf?
Unless Joe was more of a "cousin-in-law" to the Jennings kids. So let's say that Lenore had two daughter: Eunice and Sophie. Eunice marries George Jennings and they have three kids - Tom, Chris and Amy. Sophie marries Stanley Haskell, but they have no kids. However, Stanley has a brother named Edgar who marries Martha (nee Stamborski) Haskell. They have a son named Joe. Sophie and Stanley Haskell would be the aunt (by marriage) and uncle (by blood) of Joe. By extension, but not direct blood, Eunice and George would also be Joe's aunt and uncle, so their kids - Tom, Chris and Amy - would be his "cousins", or what I would call "cousins-in-law", since Joe is not directly related to the Jennings kids by blood, but only by marriage. It does work. I drew the chart lines to see. To simplify it: Joe's father is the brother of a man married to a sister of the mother of the Jennings'.
Gerard