First, the two basic rules. Rule #1: your player is not the exception to any rule. Rule #2: there are exceptions for every rule.
Second, about academic majors. Statistics reveal that well over 50% (some have it as high as 80%) of college students change their major from what was indicated at matriculation. For an athlete, if the initial choice was in STEM, that number will be higher (in all but a handful of schools (all D3)) - and the final major will be much easier (less math, science, engineering) than initially desired (more intro to coin collecting, rocks for jocks, etc.).
Third, about the intersection between majors and baseball. The higher you increase the chances of getting to a CWS, the more difficult it will be to have any "hard" major; even at the Ivies - at the other end of the CWS continuum - most players will move to an easier major. There are simply not enough hours in a day, energy, or desire to focus on or master academics - where every normal student is already focusing while you were at practice, on the road, lifting, etc. Whether it's from the coaches, peers (players), or internal pressures, academics takes the hit.
Fourth, preferred recuit. There's some great information earlier - and it's very nuanced and contextual. Again, the greater your CWS chances, the more difficult to actually get playing time. Now, if a kid is costing the team nothing $$, and the kid is a positive to have around (e.g., eager bull pen catcher), and the kid is gung-ho and accepts the role (e.g., no making the travel roster), the kid has a spot - IF HE MAKES THE TEAM IN THE FIRST YEAR. (I'll note that if Rule 2 applies, if the kid earns playing time and delivers, he'll get $$; but see, Rule 1.) [Also, all bets are off when the coach leaves.]
Fifth, look around what's happening in teams with legit shots at the CWS and it's effect upon a HS player's choice. The LSUs, Texas', don't stop trying to upgrade; the upgrades - portal - cause a cascade effect where players displaced from those teams go to mid-majors, etc. Combine that with the coaching carousel - mid-majors trying to move up, fired big guys moving down - and there is no way a person can accurately predict what most programs will look like in 2 years. (Don't even think about proposed rule changes on schollys and coaches.)
My current theory is the higher the probability of getting to the CWS, the harder it is to even speculate what a players career at a college will look like baseballlwise.
Which brings me to Rule 6 leverage baseball into the best academic school he can get into; he's not Rule 2. Even if he were Rule 2, it's doesn't matter for proball where a kid plays, if he has a potential MLB tool he'll be found. Where he plays does matter, however, for probabilities of getting to the CWS.