Focus on developing the most important feature(s) first and work towards producing the simplest version of the app running with a minimal number of features working. Don't get tied down with compiling a large and untested project at the end of the event.
Divide and conquer: Choose a development approach which allows each team member a way to get engaged immediately. Use an app like Trello to track the features you are developing and the tasks that team members are pursuing.
Create UI menu stubs and objects to show functionality but delay implementing them if they are not critical. For example, don't waste time implementing a user login system, this is not the novel aspect of your app.
Yes, if you have other skills such as problem solving, presenting, domain expertise, or have a passion for improving our world join a team and contribute. Your skill sets and passion could make all the difference.
Who owns my intellectual property?
The team developers own the IP they create.
How are the applications judged?
Judges will use a judging rubic to score the deliverables. Team with the highest score wins, with a tie break criteria should it be needed. See Team page for more info.
Can it be a project I am currently working on?
The application should be developed at the event. You can leverage libraries and frameworks to shorten your development time.