this looks like it could be an interesting game to try out later (only so much free time available) but I have a quick and maybe simple suggestion:
The option for the school to be an all girls or all boys school instead of capping at 10/90 or 90/10 (depending on the slider) as a future option.
I did not see a mention of it when looking through the paid for options for the game but might have overlooked something - if so, please ignore.