Your problem is that the success depends on execution.
We do know that there is market for good educational software. Many successful apps already validated that.
If you write one more good educational software, chances are you'll be successful.
However, chances are that your software will not be good in which case no success for you.
Another problem is that you might be trying to bite more than you can chew. The idea of comprehensive software product is good but if you try to build that as your version 1.0, you'll likely fail. Start small and build on your successes.
I see where you're coming from though, that you want to offer something that's greater than the sum of its parts, a single place where kids can go. But it's going to be difficult cracking that chicken/egg problem.