Welcome to the site. I agree with others that academics and other family considerations should be above baseball. But I think you get that. And, at the same time, if baseball is a primary interest of one of the kids, you will certainly want to put some attention there. Given that you have choices, I'm sure you wouldn't want to send him to a school that has either no program or a very poor program. A quick glance through Maxpreps shows that only one school on your list has been historically weak in baseball. So that may be worth looking at.
Be aware that there is often much turnover with coaches at HS's, so considering your son is 12, the current HS coaches may very well not be there for any or all of his HS years. But, if the HS has a decent program history, it is at least likely that they will continue to do so.
Also, regarding your assumption, yes Florida is in a relatively good region in terms of opportunities to be seen. But, in case you are not aware, most opportunities occur via travel team events, showcases, etc. - typically far more so than HS baseball events. So, again, this gives you the opportunity to put more emphasis on other aspects when choosing a HS and then finding the right travel organization when the time comes for better baseball exposure opportunities for that particular child.
And, certainly, former MLB LHP's would be a great resource for your son. But, again, will they still be there in 3 years, 5 years? I would guess that you will have access to a reasonable abundance of qualified P coaches in the Tampa area that you can tap into via private instruction, regardless.