I'm not shore how, but I have way to much money very soon in dynasty. First day(s) they don't really need a home, bed and fridge and toilet will do. When I started just with Jamie Jolina (she bring around 20.000), until generation 2 became YA there was more than enough money for nice house, and until generation 3 is born they had thousands of simoleons.
In last attempt (still active) I moved in Agness too, and join firefighter career for founder, so by the time second generation reach YA they are worth around 750 000 plus 2 properties! At first I made them small home that has only 2 small bedrooms, just a regular home up to 50.000 furnished but with all that sculpting, painting, photography, writing and medical and firefighter career, they are already insanely rich (and Agness is still living on normal lifespan). Only now I'm building huge home, that is still not as huge as in previous attempts because of the file size. One large bedroom for all immortals to sleep in and one large bedroom for current immortal too be (and it's spouse and child). I'm not planning to add nursery etc. One empty room for sculpting, and outdoor party/skilling areas. Museum is part of basement that has no stairs - to keep portraits and ambrosia out of reach. First mansion I made for dynasty had 9 bedrooms including tomb themed hideout, and so many things, but file became so huge and eventually I had to gave up on them because of that, so keep that in mind from the start.