I'd thought that pmarca's comment here was hyperbole, but apparently it's fairly true these days:

https://news.ycombinator.com/item?id=8024239

Anyway, to respond to your comment, non-profits have to file articles of incorporation and bylaws with the state when they incorporate:

http://www.idealist.org/info/Nonprofits/Gov3

Among the information necessary is the purpose of the organization, which answers #1-2 of your questions. In practice, #3-5 are decided by fundraising activities of the organization; it is part of a donor's due diligence to ensure that the non-profits she donates to are the most effective places she can find to employ her capital. Non-profits that can't convince donors of this end up going out of business.