How awesome of you to give this pair a home. They are adorable!
Your housing situation looks great. If you can, I'd let them free-range by day, and then put them into the pen at night. They will need a kiddy pool during warm weather, and can get away with a 5 gallon bucket or rubber tub in winter.
Geese have similar diet needs as horses. They are grass/hay grazers, with grain supplement. Flockraiser is a good all-around grain. I also like to give them whole corn. I like to feed approx. 1 cup per bird twice per day.