i attach a simple monte carlo engine in c++ and matlab code. to my understanding, the assignment asks u to price the structure with MC not close form ( i guess you could use it to double check your pricing). use the engine to price the derivatives and implement the interest rate SDE you want to use instead of the constant interest rates. change the payout accordingly. For pricing the 7 year zero coupon bond, most probably you do not need the SDE but it is up to you.