Maybe the FF just links to people with very sad feelings, like Schala upset about what she did to her kingdom and Riddel saddened by ''Dario'' (or Zolander or whatever his name is in RD)'s death?
So now Dario is her father?
Anyway... Could be. I just don't see why sad emotions...
By Dario I mean her boyfriend... mmh she has one in RD right (I've only played it once a long time ago)? If she doesn't, then her father's death could do it too.
I said sad emotions because that's the only link between Schala and Riddel that I can think of (well except if the FF just likes cute girls
). The FF did grant Schala's dream of forgetting what she did and giving her a new, innocent life, so perhaps the key to having one's wish granted is a strong and sad emotion (Riddel surely would like to see her father revive).
Also, we shouldn't forget that the Arbiter stuff was something invented in CC. In RD the FF is just a non-living jewel.