This was my response to what Daryn posted.

The only real problems I have with your explaination is that Crono and Marle are not mentioned in Cross and there is no reason to believe that they died.

The other thing is that I don't believe Balthazar is everything you say he is. He is smart and has read the history of the planet up to the point where he was at and made some guesses. He knows of things to come but the one thing I will call you out on is telling Lucca to start up the orphanage. Lucca had already found Kid in that forest area as revealed in the anime ending of Trigger.

I don't believe Harle needed to convince FATE either to trust her either. I think FATE was going to use her just as she was going to use him. I think he realized that there would be nothing Harle could do once the door is open. FATE would have had control over that room once the doors opened and that Harle would stand no chance alone but with FATE operational the dragons would not have been able to become one again. I believe FATE knew all of this and decided to use someone who had the same goals and great powers to assist him in his quest. Harle played along because it was the only shot she would have had at obtaining the Frozen Flame...no matter how slim those chances were. You can see she saw an opening by helping Serge to regain his original body so that he would be able to open up the door. That would be her chance while FATE is confronted by Serge and Co.