He sounds like a challenging bird. I guess the bigger question is does he have the traits you need him to have in order for him to be successful in your home (a keeper)? I find some people take on a rescue because they want to change the bird and if they can't, they rehome it quickly. Other people take on a rescue bird with a degree of acceptance that the goal is to get a good relationship out of it but still accept it if they can't. The latter is really the way to go. If he is a one person bird, screams and biting in your home is that a problem for you? Some rescue birds you can fix. Some you can improve slightly but still have to deal with a difficult bird for the long term. If these behaviors are well established, its going to take some time to get rid of them.
Being a one person bird might not be super fixable. Others in the house can work on having a hands off relationship with him by doing some hands off target training and trick training. But he may always be unpredictable. Screaming is hard to get rid of. I'm hit or miss with that one myself. Biting and aggression don't really phase me much if I'm taking in a rehome. The goal is to make the bird happy. If he wants to bite, I'm fine with being hands off. You might not be. Some people want so badly to have a cuddle buddy that they quickly loose the compassion when their hands get sore and scabby from the bites.
Also, just as an aside, if you decide to get the bird, don't let him roam around on the floor. That leads to so many hard to fix problems and habits.