So after reading through the rulesI can say I like what I see. The fluff and flavour sets the tone nicely while the illustrations complements it just as well. Rules are clear and simple, while Mech building is also fairly simple and still offers players with a healthy amount of choices and decisions. All in all its a excellent example of a rules light mech TRPG and I don't think running through the academy shouldn't take too long, maybe one to three sessions? (I can't really say until I or someone else brings it to a table and plays).
I've got mixed feelings about losing Influence after moving to the Unit phase. On one hand it makes sense being the head of the student band or being the daughter of a wealthy industrialist will matter little once they are part of the Unit, on the other hand I'm not a fan of dropping a mechanic that was there at the beginning. However I think that's just me, and if it is an issue, I doubt it will be a big one if the academy only takes a single session.
Besides that issue (which probably isn't really an issue) everything is absolutely solid here, and I think you've practically nailed what you were going for.