Basically, they weren't certain about my programming skills, so they called Foo and Bar to "manage" the project.
Right here, is when you should of walked away.
If your trying to win "who's way of doing it is right"
Prove it - find articles, websites, etc... on the best practices of writing code in Python - schedule a meeting and nicely, show them the current code, show them the proof that you found to back up the way you did it. If their decent people, they'll understand and let you do it your way. If their stubborn, they'll push back (as they have) and you can deal with that then.
People are generally hired to do a job because the people hiring them think the person their hiring knows what their doing. If their questioning that, they may not be very knowledgeable in what you do (obviously, as many non programmers have a hard time explaining what a programmer does). People also get comfortable and don't like change. If they've worked with Foo and Bar in the past and they asked them to take a look at the code, they obviously trust their opinion. I don't think this has anything to do with you and your skill set - it's more on them and their lack of willingness to work with new people.
I now have this semi-usable software as an open-source project.
There are A LOT of schools across the world. Tens of thousands. Some formal; some alternative; some people home school; if you had a need for this, others might as well. Wether people know they have a need for it is a different issue and getting people to use it will fall to marketing, as any other project would. Will it hurt you to finish it / keep it on Github? So long as you have the time and willingness to work on it, I don't think so. If nothing else, it might look good on a resume. How far you want to take it is of course up to you.
If you really want them to use this software (free or otherwise) - remove your emotion from this equation. Finish up the software / make it look pretty / fix any bugs you can. Schedule a meeting and do a presentation. Explain the value of the software over the old software; perform a demo; explain how it will make this process easier and why you think it's the right way to continue. At this point, your a salesman - you need to sell them on the idea that what you've created works and works well and that they need it, free or otherwise. If they say yes and allow you to implement it / want to use it - great! If they say no - you weren't getting paid for it anyways. Chalk it up to a learning experience and move on.