Yes you can rename the buildings and property to anything you like at any point in the dynasty.
As for the getting over having a lot of people, if you have elders that don't really do much that are into their immortality. Depending on their skills, you can have them retire and just do something that will take all day. Or what I did in my steel dynasty was have them play video games all day. If they're doing something like that, you don't really need to check on them very often so you can concentrate on the ones who aren't old and immortal.