Most people would say snaps are more secure than velcro, so I'm surprised by your predicament. Maybe the problem is you have too much tension in your strapping, in which case slightly longer straps or straps made of a stretchier material would help.
Still, the velcro I do use is industrial-strength velcro, which you can get at Michaels, Jo-Ann's, Home Depot, etc. It already has a sticky back surface, so no glue is required.
If the snap plates are glued on, it depends on the type of glue he used. Assuming he used ABS cement, I've heard freezing it helps to weaken the bond, after which you carefully pry it apart.