I don't see what the problem is. If one uploads a sim/household that does have stuff from other packs that one does not have, or CC, that is just gone or subsstituted. (Weird fact, I got a toilet from a pack I don't have, a medieval toilet or something, downloading a building for a lot. Only for that lot, I couldn't replicate it, obviously)
I have shared one Sim and apparently there was no problem. The only way to find him, even though everything was base game clothing, hair, etc, was to have CC enabled in the gallery. Most likely because I have a mod that makes skin textures look more realistic than plastic.
