Make sure that "ground floor or elevator building" is noted as a medical necessity, not merely as a preference.
My understanding is that medical necessities are handled before mere preferences.
Will you use a car or Disney transportation? If you'll have a car, it would be good to be in a building with plenty of parking. If you'll use Disney transportation, you might want to request a room near a bus stop.
Crutches are fine for short distances, but you'll probably want to use a wheelchair around OKW and at the parks. Disney resorts are supposed to be able to supply a courtesy wheelchair for the length of your stay (based on availability). Not all cast members have the same understanding, so if someone claims they can't help you, ask for a manager. If no wheelchair is available, ask them to borrow one from another resort.
If you rent a wheelchair at a park, you can save some money by paying for several days at the once. However, with the courtesy wheelchair from your resort, you should not have to rent a wheelchair at the park at all.
Sorry to hear about your foot. Have fun anyway.