Cabbagedad, I'll try to answer these questions to paint a clearer picture. Initially, I wanted to be discreet with this post, as I don't want to involve anyone but myself, and I still feel that way. However, I know if I have more questions, I could PM you or someone else to find more answers. Here it goes:
My player experience is very limited. Other than playing some in middle school and a variety of backyard ball, I've never played on the high school baseball team at my high school. I wasn't interested in sports in high school, as family issues and a desire to pick up my grades led me to not pursue sports in general (not to mention I wasn't very talented overall, although with practice I could've been okay).
Our school has a small high school population--we have a combined middle and high school (6-12) with a population of around 8-900 in all grade levels, the population predominately being middle school as well (high school population is around 350 students).
Our school is also a school of choice, which is a public school that students must apply to in order to be selected via lottery. Our school has a science, technology, engineering, and math emphasis (STEM), and students must have a certain GPA in math and science to be eligible to enroll.
The school would begin with junior varsity for a couple of years before being eligible to play varsity ball, in which we'd compete against numerous other high schools in our city and district (about 4 other public high schools in our city; 3 or so private schools as well).
The sports our school has as of now are girls volleyball, girls and boys basketball, and track and field at the high school level. One reason our principal is so adamant about starting the baseball program is that he doesn't want to see students leave our school to play ball for other schools in the surrounding area. As far as softball, not enough students have signed up, so that's a no go for now.
Our population is predominately middle to lower class students, as most affluent people in the area usually attend private schools, although this isn't always the case. We do have great parental support at our school, which is a major plus.
As far as summer baseball, I know the area is very active with a variety of leagues, so to get our school involved would not be a major problem.
A practice field is all that would be possible for now on our campus, as I don't believe the dimensions for a full field would be possible at this time. I think our AD said a baseball or softball field would be around $40k to develop, so that's out of the question for a while. Much like our budget otherwise, we have no money to develop the field, although we may be able to borrow equipment from the school board to develop the field overall.
Hope this info helps.