Do I understand your program? You will make a loan to a freshman for the cost of the first year of tuition. The loan has a 12 month term. At the end of each 12 month period you refinance the balance of the note, plus accrued interest. At the end of four years payments are deferred for six months. Then is the full balance due and payable or is the loan converted to an amortizing loan?
Confirm that I understand your proposal and then we can discuss documentation options. If I understand your proposal correctly there are a number of easier options that you may choose to pursue, if your systems are capable.