He'll need another bathroom break anywhere from 30 minutes to several hours after the evening meal, depending on his age - it'll be your job to figure this out. He should get another airing right before you go to bed. Rescue dogs come from a variety of backgrounds, but all dogs can do with more socialization. Now you can start inviting your friends and relatives over. Do introductions to new people gradually.
Introductions can take the form of petting, playing fetch, even going for a walk.
Don't reach for the dog right away - let him come to them. If he does not go to the new person, that visitor should completely ignore the dog. Patting a dog on the top of the head is interpreted by dogs as a powerful dominance attempt and can be a challenge to some dogs, a frightening thing to others. The opportunity will allow you to determine how your dog responds to strange people, dogs and places. Authority without domination.