If your son can play high to mid level DI baseball, I would make the top priority getting him to the 17U WWBA in Emerson next summer. Otherwise, getting to that event is less important in terms of recruiting.
IMO, the most important factor for most kids is getting seen by the schools who might want him, and the more times the better. You say that he could return to the same team, so you should have a good idea how many recruiters attended the games this year. Do you think he would be successful reaching his goals with that? If not, would the 17/18 team be any better? If not again, then reevaluate the plan. Should he be trying out for another team that's better suited to get him in front of those recruiters?
Good luck.