I need advice on red fox and black cat

Been playing the game and I am enjoying all the side quests but especially the two double crossing siblings. I looked up some info and apparently I'm either gonna end killing them in a boss fight or they kidnap Gepetto, is there a way to avoid both of these?? I just gave them the fruit, when will I next see them??

If someone could just provide me a full short guide that would be greatly appreciated.