Sorry. I just read your second paragraph.
Unfortunately I won't know definitively about the job until just two days before school starts. My loan distribution will already have been issued by that time. If I withdraw on the first day of school and get a full refund of all tuition are the loans simultaneously canceled? Will I owe anything (fees, etc.)? Or can I keep the money and just start making payments in six months? Any help from anyone who has dealt with this is appreciated. As much as I want to go to law school, I have a hard time turning down six-figures a year for something that is largely a personal satisfaction type of endeavor.
If your loans have been completely disbursed (I'm assuming that when you say your "loan distribution will already have been issued by that time" that you mean that all of your loans have been disbursed, including COL, and the COL loan money has been transferred to your personal account already), this is my understanding of what will likely happen:
Tuition: if your school refunds the entirety of your tuition if you withdraw before the first day of classes, then your tuition will be returned to your lender. You need to look at your school's tuition refund policy to figure this out.
School Fees: will not be returned. Most schools only refund tuition. Generally, the fees are "earned" by the school when you enrol. You need to look at your school's refund policy to figure this out.
Any Funds in Excess of Tuition and Fees: you can "keep," but you will need to repay.