Everyone has given good advice so far. In my own experience introducing two macaws is like introducing two children. They may be best friends from the moment they meet, they may take a while to become friends, or they may be mortal enemies at first sight. Macaws can take months to get to know each other. They have complex emotional needs that are constantly changing, and hard to understand. I did a very slow introduction between a buffons and a green-wing. They were in cages in the same room and allowed out on their own cages. Over time I moved the cages so they were close to each other, but not touching. This lets them see and vocalize with each other, but not physically interact. I would let one out at a time so they could crawl around on the cages and have more interaction. I kept an eye out for biting or aggression between the bars. Eventually, they were both allowed out at the same time and they had supervised physical interaction with each other. I kept a cheap throw pillow handy just for that reason. Breaking up a pair of fighting macaws is not something I want to do, so I figured tossing a small pillow at them would be enough of a distraction that I could break them up if they really got into it. Luckily I never had to do that and they got along really well. They had complementary personalities and it didn't take long for them to bond. The male buffons was very reserved and quiet. I believe he had been badly abused by his former owner. The green-wing was loud, crazy, and high-energy. She was the life of the party and he was the guy standing in the corner. When she got out of hand, he would reach out a foot and grab hers. She would calm down. Over time, she taught him to unwind and start to be more active. They have been good for each other, but they are no longer pets for me. Neither of them wants any physical interaction with me and I respect that. Now they live in a large flight cage with a nest box. He started sleeping in the box, she slept outside. Over time they have both started sleeping in it. Are they ever going to breed? Who knows. If they do, great, and if they don't, they don't. At this point in their lives, they are happy birds and that's the most important thing to me.
I have a breeding pair of green-wings, but sometimes I question their bond. During breeding season the male is very dominant. During the offseason, the female is very dominant. Sometimes they fight and she acts terrified of him. They are productive, but I don't often see signs of affection between them. However, the one time I tried to remove him from the cage to get his nails done, she screamed like she was being murdered. I was afraid the neighbors were going to call the police because she sounded like a woman being attacked. Are they bonded, or do they just tolerate each other?
Many macaws won't breed unless they are comfortable with each other, and with their surrounding. Just because they are bonded doesn't mean they will breed, and putting two pet macaws together may cause you to lose them both as pets. I do know of someone who has a pair of blue and gold macaws. They are both living pets with him and they are bonded with each other. Every other year he gives them a nest box and they give him two chicks. They want another to do with him while they are breeding. When the babies are removed, he takes away the nest box, and in a few weeks, his loving pets are back. This kind of behavior is certainly the exception and not the rule. I was lucky that the buffons and green-wing were able to get along, but it took months to go from being side by side, to sharing a cage. He had never been around other macaws, so it was a relief that they were able to get along. The real question is, are they bonded, or are they just companions who live together peacefully? I have no way of knowing that.
So I guess the answers to your questions are there are no solid answers. Each bird is different. Each pair is different. Can you have pets that breed and still be pets? Sometimes, but it's not common. Breeding is rewarding and heartbreaking. Expect the best, but prepare for the worse.
