but )(IC doesnt stay all the time on alternia, does she?? like, she's got other business than taking care of potential heiresses, another young, stronger fuchsia challenges the aspiring heiress

We don’t even know if there are more than two Fuchsias at all. And Condy comes back for her, since Fuchsias can be in fact a threat to the throne. In Alternia specifically, too, they share the same Lusus, so one of them gotta go.