“Here’s my guess...
This pathetic loser didn’t know this guy was the boss of the Gambino family. He wanted to date the niece, the “boss” said “no” and our hapless dimwit offed him in a fit of rage.
Then he learned the extent of what he had done. He knows he’s dead. He knows it won’t be quick.
Derp(s) got to him before the hearing and offered some level of protection in exchange for his new artwork.”
I am buying a ton of unbelievable information. I cannot believe this. There are no coincidences. This guy just happened to want to date this girl. This girl just happened to be with the mob. This guy did not know the girl was a mob associate. So, because he could not date the girl, he killed the mob boss. Come on... Who is buying that?
I agree with your takedown of the other theory.