Woah.
PAL to NTSC is MUCH much easier than that. I've done a ton of movies. Use TMPGenc. Don't go to AVI.
There's really no reason to do any of that.
Hell, you don't even have to convert the sound to a wav.
I could do the conversion of the main movie in one night if you want me to send it to you. 4gb. done. You take care of the menus.