Having a prior JAG (or anyone with a few years of military experience) review your contract with you is probably a good idea, since it will allow a "neutral party" to explain to you what everything means. The contracts are written in fairly plain English, with very little "legalese." The "neutral party" will be able to point you towards the governing statutes/orders/directives if anything is unclear. Now, will you be able to make changes? Don't hold your breath on that one. Remember, there are 100 other candidates who would gladly take your place if the standard contract is not good enough. Like Boomer said, though, it sounds like you have a pretty good handle on what you are getting into.
One of the things that has always chapped my ass is when someone says, "My recruiter lied to me!" or "Why doesn't the government hold up ITS end of the contract?" Well, when I was 17 and signing page after page and Statement of Understand after Statement of Understanding, I actually took the time to read what I was signing. I knew full-well that I was signing an 8-year enlistment contract - the same 4-year active, 4-year INACTIVE contract that everyone else signed. I knew full-well that my service could be extended indefinitely during periods of national emergency. Hell, there was even a part of the contract that said, essentially, "I am guaranteed NOTHING except what is written in this contract." When I was accepted to MECEP, I read and understood all orders/directives before I signed and raised my right hand. When I was accepted to flight training, I clearly understood that I am obligated to six years after winging as a rotary pilot.
The contracts/SOUs were all in plain English, written so that a kid with a New Jersey public school education could understand them.
Whew - why did I get up at 0500 again?