IC D&d 3.5 magical academy
Just my two cents... 8th level gestalt does seem a bit high for a strict Academy.
I would suggest you start out by figuring out what kind of classes are being offered. Things like alchemy, herbology, and any of the Craft feats come to mind. If there is a psionic curriculum, that's fine, but I'd still want one of the character's classes to be arcane. The Adept idea sounds like a good work-around.
As for the Charm spells, perhaps the Academy has a ward against that school of magic... except in the specified classroom.
You don't need a lot of detail to get started. For example, you don't need floor plans of the Academy right off the bat, just a general idea of the main building, how many towers, etc. Of course, if you have a map of some other place that you can use, that works, too. Likewise, is the Academy run by a single wizard or a council? Full character sheets for them and the teachers aren't needed, but if the head is the wizard Aristobulus, then you should know he's 15th level with a 19 INT and 17 CHA, etc.
The only other thing that might be a good idea is that when players apply to the game, require their characters to have a motivation for attending the academy as well as a goal. For example, Makron the Fighter/Adept might want to gain spell abilities so that he can free his father from the influence of the Grand Vizier. That way, the character has something to accomplish and the player has a direction to steer his character.