A few observations.
A 2022 has three semesters of grades - two of which most schools don't look at; great work on the GPA so far, and, I assume, he's taking the most rigorous courses his HS offers (you've got to check the "most rigorous" box to have the shot at the HAs). If you haven't done so, lock down all your academic questions through meetings with his guidance counselor.
Scout ball (definitely alive and well in NorCal) is a great option (it was my son's only "travel" team).
Over half of HS kids will ultimately change the major from their initial HS choice; and, even if the kid stays in the area, some schools have better sub-specialties than others (e.g., Engineering has many, many different sub-areas.) So, start with a list of schools broader than his current choice but that fit his academic profile.
Assuming his academics stay on course, I'd try to get into the Stanford and California HF (and like) camps for THIS summer. (My son did both as a rising junior and both opened the right doors.)
I'd also use the summer to prepare him for the ACT/SAT and take both at their first fall testing dates. Its a huge advantage to have testing done early (Sept of junior year).
If you've winnowed down your school choices, start sending e-mails to the coaches to find out their summer schedules. It's possible, for example, to combine an east coast baseball trip (to a camp/showcase populated with your target schools) with a campus visit(s) which will put a face on a far away college as well as demonstrate interest to the coach.
I also note that you're college list includes "top D1 schools, some less competitive DI schools, and a few NAIA schools spread out across the country." That's a pretty ambigious description, so it's hard to drill down. But, if it's based upon baseball (as opposed to academics) AND the major you're thinking about today is difficult, begin educating yourself on the intersection of baseball and academics at these schools - there are lots of threads about the life of a college player at various categories of colleges. A hard, academic major is incompatible with baseball at, let's say, LSU; not so much at Bucknell.
I think you're asking great questions. It's not REQUIRED to do showcase and tournaments; that is one method of exposure, and there are many paths to getting exposure. Planning is the key.
Welcome and keep us informed so as to help others coming along the highway!
PS. I'd also give him lots of reps at third and first base; make him more than a catcher.