1) Yes - you're going to need an Enterprise Account AND let Apple know you want access to the MDM documentation and libraries. If you're doing your work on behalf of a company I would recommend finding your local Apple Rep in CT. I have a pretty good idea as to who your rep out there is so let me know if that's the case.
2) You may be able to dig up some tutorials (or people that know some) on EnterpriseiOS.com though that site is hit & miss. If you're looking to do everything from scratch (including the APNs server) there are a lot of git projects out there that handle it.
3) Once you take care of step 1 there are some other documents out on the Apple site that discuss the calls in detail. This document covers a lot of the protocol as well.
Good luck!
EDIT: Anyone looking to take this route can contact Apple Developer Relations at 1 (800) 633-2152 Mon-Fri 9:00AM-7:00PM CST.