My theory on the family

I think Dana got pregnant from Louis when they were possessed in the first film. Nobody new and Dana gave the baby up for adoption and left to pursue her music career. The baby grew up and is now the mother of the family in the film. Being the love child of the Gatekeeper and the Keymaster has to have some ramifications. This would explain why Dana is brought back into the new film. It would link the new family to the old film.