SKcanes, welcome to high school baseball web, it's a great place of knowledge sharing.
In response to your question, here are my thoughts (for what little they may be worth). Some of the events you've mentioned are things which you can sign up for and play in. Other events you've menioned, Tournament of Stars, Area Code tryouts, any of the national teams run by USA Baseball, are things for which you cannot sign up. The only way to participate in those is by invitation, and there are relatively few spots allocated for the number of aspiring baseball players who'd like to do those things. I don't want to discourage you, but players can't just sign up for most of these things.
I'd suggest your son work as hard as possible in the classroom to maximize his opportunities, and get on the best caliber travel/college development team that you can find. Those are the first steps, and after that you can sign up for some of these showcases. I'd highly recommend Perfect Game's showcases, and think they set the standard for all the others.