So Hollingshead is the Spinas' cousin. Something here still does not make sense. Why would Vena allow Panozzo to rob another guy's home who is in that crew? Particularly a guy who is so high up and a cousin of the Spinas, 3 of which are in the Grand Avenue crew. There has to be something else going on.

Perhaps the Spinas are out of the rackets, or Panozzo conducted his activities without the permission of Vena, or Vena has no control over his crew.

There are too many unknowns here to speculate. An alternative theory regarding Zizzo is that Sarno took him out without anyone's permission. This is a likely scenario as Zizzo was close to DiFronzo, who also reportedly had issues with Marcello. I think that Sarno was allowed to run Cicero his way after Marcello went to prison, providing he kicked up some $$ to DiFronzo, who looked the other way on things, not wanting to get the two big Outfit crews into a battle.

Although none of this would explain why Vena was involved. At the time, Cozzo was the Capo of Grand Avenue and it is unlikely he would have sanctioned Vena to take out Zizzo. Unless of course Vena was assigned to Cicero at that time. Who did Vena come up with?