The first idea is a good one. Are you aware that GC has some courses that allow the student to get credit at the university level? Tutoring at any level is important. Students sometimes "get it" when dealing with a peer as opposed to a teacher. It's a great way for kids to learn to help kids.
As to class size the last report I read was that class size in GC is somewhere around 25-27. To get down to 18 you would need to hire an additional 250-275 teachers. At nearly $50,000 a pop, that could run into millions. Then, if you could hire that many, where would you put them. Old schools were closed. To my knowledge most schools don't have room for music right now. So factor into your new budget, new buildings. Class size will always be a problem in a lower middle class community.
Neptoism is as old as politics. Is it right? Heck no. Will it go on no matter who sits on boards? My guess is yes. As for hiring coaches instead of teachers, can you give an example. If it happened, it's not right. Sports are great but education is the primary responsiblity of schools.