1. FCP X, No need to use proxy for ProRes 422.
2. FCP X, Using ranged based key words and smart collections will help you organize your footage fast.
3. FCP X, What kind of clip metadata are we talking about?
Disclaimer, I have not used AVID. But, I have used PP and for me FCP X with its ranged based key wording, organizing footage is faster and much better than PP.
Is this a multi camera shoot where all four cameras are on the interviewees?
Did you record audio separately?
FCP X is a top notch multi camera editor.
You can certainly do this in PP or AVID, but I would choose FCP X.