Indeed, but later when you enter the Wonder Bridge, the Dark Trinity appears and tells you that Geechisu broke out of jail and is escaping and all those stuff :) If my sister's translations are correct. As for N's mother, I think she is probably one of the goddess or maybe she divorced with Geechisu or something like that. :D
If you chose Celebi, you won't encounter a Zoroark, instead, you will encounter Zoroa, (my mistake :<) And yea, I think it's stronger in the Lost Forest, perhaps I got the levels wrong~~ XD