I agree with your thoughtful analysis completely except for the final conclusion. I believe some traits are binary.

I've always been intrigued by the WWII Enigma project. Alan Turing worked on it and was one of those geniuses who could figure out things in ways other people couldn't understand. He was homosexual and eventually committed suicide because he couldn't change that. I've always thought that if he could have altered his sexuality he would have, and therefore it must be genetic.

There are some traits which are pretty much binary. Whether aggression and violence are included I believe is doubtful. I suspect they are probably shaded, there are gradients, and there is room for environmental factors to influence them.