Just on the surface it sounds like someone who had high aspirations in life, but failed to achieve, probably due to social ineptitude. Heaven only knows how he tried to buttress his ego, but in the end the whole house of cards came crashing down, at which point he decided to end it all, making a big statement as he went.
I think your explanation is pretty close to what it is.
Possibly. He looks like a very angry person in his photo (no Buddhist meditation there!).
So far as I know, they’re still looking for a second person, so perhaps he fell in with some angry ideology that “justified” this and made him feel that he was doing something heroic.
His father is very involved in Dem politics in New York and also seems to consider himself “Mr. Trinidad,” judging by some voter information on him, so who knows?