This may or may not be common knowledge, but once you complete this aspiration it will autocomplete for all members of the household, as long as the lot remains eligible. To be honest, the reward trait is not that great, and it is wonky so it doesn't always work.
However, it is a good idea to cycle every household Sim to the aspiration once they age up to teen, because it will give them an easy boost of satisfaction points.
Fabulously Wealthy must be earned on an individual level though. Sims will need to grind that one out regardless of household wealth. It has a much better reward trait though, and it seems to work more consistently.
Hope that helps someone.
