I would quilt around the appliques, and just fill in either a cross-hatch in the background, or a stipple. If you aren't confident with FMQ on machine, can you hand-quilt?? Stipple would be easy enough to hand-quilt. Or, just machine a cross hatch, SID the applique and around the border. How about adding a heart applique in two opposite corners of the border???? Just a thought. It is really cute-I'm sure he will love it!!