Oh goody, I love Dean too! Can you believe it's been 11 years? Love that show.
One question though. I thought I read somewhere that we can't marry our sims to existing families in the sims universe. I think maybe I'm wrong on this though as no one said anything in my first attempt. I may be mixing up the different legacy rules. Can we marry anyone in town and move in whatever townies we choose? Just need to clarify.
Yes you can marry your sims to existing families, only if they do not have any previous children. You can't move in with them, they have to move in with you to your dynasty lot. The targeted spouse must not have any previous children. Also sims from online gallery is banned, make sure you start your dynasty on a fresh file virgin town.
You can move in whoever you want, but you can't move them out once you move them in. They must remain in your dynasty house and die of old age, no intentionally killing them off. Be careful because your household can only have 8 people max, if you move in too many and they haven't died yet, then you can't produce heir.