You are over thinking this.
1. Boots that fit, make sure they are tight, you don't want him sliding around when he's learning.
2. Bindings that fit the boot.
22. Any freestyle board made in the last 10 years around a 150 will be fine to learn on. He's a kid and will learn fast on it.
Rocker will be easier to learn on but camber will be fine.
Yuk yuk. We should sticky this post.