BUT keep in mind that if you are sloppy and anyone sees it, you will cause a school lockdown, you will be detained and possibly arrested. You will have an affirmative defense for the carry but they might get stupid and charge you with disturbing the peace.
I bolded "and" for a reason. If it was "or" you would be GTG as you would only need to satisfy 1 of the requirements, however, since it is an "and" the state would argue that you would need to satisfy all three requirements (though I doubt LEO's have a local and AG issued permit).