You use up 6 months of your grace period, and then apply for REPAYE. Your interest will capitalize, but you have an income of $0 (presumably--it depends how your stipend is paid) and will have no (or minimal) monthly payments and your interest rate will effectively be halved by the interest subsidy.
Then when you graduate you enter repayment immediately (no grace period left over), so you can legitimately say you have no income when you re-certify your income (because you won't have started internship yet) and will have $0 payments for your first year of internship, along with the huge interest subsidy.
I would avoid putting your loans in forbearance--your interest capitalizes and will grow at the normal rate. Unless your entire stipend is taxable and considered income, then you save a whole lot of money by using REPAYE.