I have been reading this thread for a few days and thinking about what to say. I am not sure that I am quite sure where to start, butā¦
First of all, this is a process, and this web site is a good place to ask questions. Your son sounds great, and has a decent GPA and very impressive test scores.
The list of schools in the original post is a very, very long list. Many of these schools (if not all) will require essays. I do not see how a student could do a good job on all of the essays (or the rest of the application) for a list this long.
Many if not most of the schools on this long list are reaches even for students with straight Aās over all four years of high school. Just to mention some that I am familiar with, Middlebury, Dartmouth, Williams, Northwestern, Harvey Mudd, Columbia, and Yale are examples. UT Austin and Georgia Tech out of state are other examples. UIUC out of state would be an example if applying for CS, and might still be an example otherwise. To me the ones that look most likely include Ohio State. I do not know whether it is a safety with a 3.66 unweighted GPA, and I do not fully understand why a student from California would think āOhio Stateā when they are deciding where to apply. However, of course there is plenty of time to reflect on the list and this is a good start.
An unweighted GPA of 3.66 is pretty good. However, I do not think that it is strong enough to justify applying to this many high reach universities.
I see āpremedā and I see ābudget is not an issueā. Just to be clear, four years at most of the private schools on your list plus another four years in medical school could easily add up to $900,000 by the time that you are done. Is $900,000 affordable for you? If so, then we can indeed drop this issue.
I see quite a few relatively small āliberal arts collegesā on the list, plus a few very large schools (Ohio State being an obvious example). There are advantages and considerations both ways. It would make sense to visit a few large universities and a few smaller colleges and see where your son feels most comfortable.
Engineering is an academically demanding major. Premed is not a major, but premed classes are very academically demanding. The same is true for computer science. I do not see a lot of overlap between these potential subjects. One issue with computer science that I noticed many years ago is that sometimes a student can spend long hours trying to debug their software. These long hours could potentially take away from the time required to do engineering problem sets or to study for the tough premed classes, or to do premed shadowing. Narrowing down the options will be needed at some point (not necessarily now however).
It is very common and normal for a student to change their major after they get to university, and university will give an opportunity to try a bit of this and a big of that before settling on a major and an intended career path. However I hope that your son has spent and will spend some time thinking about which path makes sense for him. I will admit that at the time that I graduated university I still had no idea what I wanted to do with my career, and it worked out well for me regardless (I graduated with a bachelorās degree in math, which is something that can be used in a variety of ways). You son has time to think about which path makes sense for him.
Given that you live in a WICHE/WUE state, I wonder whether or not you might want to consider some WUE schools (WUE is the undergraduate part of WICHE).
And finally I agree with @vwlizard that you should put some significant effort into identifying a safety or two.