You are right in that he probably does not have just one disorder; these are just the traits that he has demonstrated on the internet. Typically people with personality disorders show traits from a 'cluster' of disorders, and the cluster Bryan (and frankly a lot of the troublemakers on the internet) demonstrate are known as '
Cluster B' disorders.
Cluster B disorders are classified as "emotional, dramatic, and erratic" and consist of Histrionic, Narcissistic, Antisocial, and Borderline personality disorders. It is possible someone can show traits from different clusters, but it is rare.
The part about Bryan that stuck out to me, is where he gets overly intimate with people he's trying to befriend to the point of making the person uncomfortable. I even recall Null once telling him to back off and stop acting like they are close friends even though they barely talked. That is a strong trait of HPD.
This is, of course, all armchair psychologist speculation, and should be scrutinized, but it is the theory I have developed.