1.) best keying techniques?
You’ve already shot it, man. Key the best ya can.
2.) best process to conduct with this sort of project? ie: trim in final cut, render separate clips then take to AE for keying and titles and thirds?
Only if it was shot horribly. I’d not waste that time if not needed.
3.) best things to keep in mind with this sort of project? ie: shadows on the green screen, lighting, audio, editing, compositing, etc.
Well, you know you need a key. Light it accordingly and make it easy in post. There is no reason you can’t just stay in FCP and bust it out lickity split.
