Hi Alaska,
You have a couple talented kids!
The recruiting timeline on this site is a great starting point. And there is so much more information here that can be searched that lays out a gameplan for helping kids play ball in college.
1) Baseball tools matter. You've listed some of those.
2) Standardized test scores and grades/curriculum matter.
It's that intersection of where a player fits athletically AND academically that helps you and your boys create a vetted list of colleges to target. And when your boys target those schools, then they're fishing in the right pond.
There are thousands of potential colleges. Kids from Alaska will be unique and valued demographically at many schools in my experience. So they have an admissions (but not a baseball) edge at some schools already.
Targeting schools (baseball coaches and Admissions reps) and expressing interest has a lot of components to it. One component is showcasing in front of coaches from schools on your sons' vetted lists. Where to do that depends on what schools are on their lists!
Sooooo, I recommend for your 2019 to start compiling a list of colleges. Then test that list...does he fit academically? AND does he fit for baseball? No guarantees on either of course, but you want to target schools that makes sense. Then start targeting those colleges. Summer 2018 is the prime recruiting time for most colleges recruiting 2019's. Top 50 programs will mostly be done by then, but most colleges will not.
For a 2021, I'd focus on getting better athletically and academically. There's plenty of time left for college baseball recruiting for a new freshman.
Good luck!