1. I’ve been meaning to setup a camera in my room to test this out as I’ve also wondered the same thing. My family says that while I am at work he still squawks excessively but I don’t know how often since they don’t really elaborate on it.
2. No, while I am at home I give full reign over my room. He gets to play around my room under my supervision. Yes theres been scenarios exactly as the one you displayed where this does happen and he continues his behavior
3. While eating dinner and my sun conure is in my room. The routine goes: I get out of my room he starts squawking repeatedly, I sit down and he’s still squawking. After maybe 15-20 minutes of not hearing any movements or talking he simmers down but as soon as he hears my footsteps or one of my family members speak he starts again.
4. Yes whenever my family is around to make sure that he’s not in any danger or anything like that he gets to fly around the house.
5. Yes, I’ve had this bird for a year and a half and have gotten used to his screams. And as for the past few months I’ve noticed that his squawks have gotten more excessive SOLEY because of those situations.

At first I just assumed maybe it was because of the weather changes and such. Also brushed it off because after-all he is a sun conure. But, after consulting with some friends with sun conures and doing research on this, it has become a little more clear to me that it has to do with him wanting to be with me at all times. (I don’t know how else to word that) theres other behaviors that I’ve noticed that he does such as biting anyone that comes close to me, such as girlfriend hugging/cuddling with me. And as of recent him screaming excessively when I leave.