Yes, you can use the pools over at the hotel. The restaurants are open to the public but you may get a discount as a Four Seasons guest. It is walkable but they can also shuttle you between the resort and residence club on a golf cart.
I don't know about a concierge, I didn't see one specifically but the front desk staff may be able to assist.
I would really recommend a car. The resort is kind of remote. It is surrounded by neighborhoods, but nothing is really walkable from the property except for the Four Seasons Resort. If you want to go out to any restaurants off site, you will need a car or would have to ride share.
