Resort restaurants are open to anyone. You won't have any problem with that.
The pool is a different question. The technical answer is that resort pools are for the exclusive use of registered guests.
DVC members staying on points may "hop" to certain other resort pools. Aside from that, only persons registered in a room, with a room key, are permitted to use the pools.
Your conscience comes into play with this pool rule because, as is the case with many Disney rules, this one is rarely actively enforced. If you ask the front desk or a lifeguard if your friends can use the pool, the answer will be, "no." However, if you don't say anything and just bring them to the pool, no one will ask to see their room key. (This type of active checking is only done at the Yacht Club/Beach Club main pool, Stormalong Bay. Wristbands are required to use this pool, and you must show a room key to get one.)
That being said, if you're going to consider doing this, please be considerate of others staying at the resort and self-police yourself. If the pool is overly crowded or there is a shortage of lounge chairs, please find somewhere else to visit with your friends.
Something else to consider is your villa's maximum occupancy. (If you're on the dining plan, disregard the following. You wouldn't want to pay for their dining plan.) You don't mention the size of your family, or your friends'. If it's just two couples, what might work is adding them to your reservation. We've done this in the past for Stormalong Bay by adding my parents to our BCV reservation. They were at their own Marriott Timeshare that week, so didn't need to stay in our room, but we put them on the reservation anyway. The studio allows up to four people and there were only two of us. Adding them wasn't a problem. They did the same for us on their reservation. We went to their pool one day. They came to ours one day. In this case, everything's on the up-and-up and there's no question about being permitted to use the pool.
