You seem like you know what you're getting yourself into so I'm not going to give you any stick about scale, however...
I suggest you DO set deadlines. Make a kick ass plan, starting with features and gameplay, then move on to actual coding / graphic tasks and set realistic deadlines for each. A good plan will almost guarentee success (also you'll need to put in work :)).
Coding it all by yourself? This is the bulk of the job, maybe you should consider recruiting a PHP/web server programmer and then a back-end socket server programmer too. You could be resposible for the AS. Just a suggestion.
I also think you should be more specific on exactly how many people you want and their role.
Final suggestion, I would think small and try and get it done while all the students are on their holiday. Then you can make slow upgrades after.
I'm going to keep an eye on this and see what happens :)