I would only do controlled scrappy for the outside - which means use as many fabrics as you like, but keep the colors the same as what you have so far - greens, browns, golds and tans. Adding other colors at this point would take away from the lovely tree you have in the center.
As far as a place to write the names, what about a piano key border? Maybe pieces 2" high by 4" long, alternating colored pieces with tans or muslin to write on.
It's going to be great!