"what does it take to get final apps working on an iOS 7 iPad"
Well most of the school made tutorials that i've seen over years, didn't really have too much code, so it may not take much at all to get it working - it might even work straight away.
There's always some work required - but the pay off will be worth the effort.
Problems to look out for :-
can't use 3rd party xtras,
can't use embedded fonts,
can't have easy keyboard entry (you'll need to redesign everything for touch),
scroll text fields need a bit of reworking,
11khz sounds files need to be set higher,
some 8 bit graphics bomb out,
there are some lingo commands that just seem to bomb out the app (work around these with other lingo commands!)
embedded Flash objects need a little bit of work to get them working right,
videos need to be in swf format.
If you're only running them on (in school) iPads - i'd say go with the side loading option.
best not to bother with the app store - if you can.
There are a few other enterprise options that might also suit.
Adobe doesn't require a cut of profits anymore, and Apple takes 30% per sale so if your app is free 30% of zero is zero. So if you did publish to the external app store you would only pay the yearly Apple developer fee which is $99, and the recurring cost of Director 12 if you doing the $20/month subscription. Your best apps you would probably want to publish externally to help others.