While online information from other people can be both useful and interesting, I always take it with a grain of salt. Because, obviously, there's no way to verify who they are or how they know what they claim to know.
From what I've read on the Zizzo disappearance, it was due to disagreements with the Marcellos and Sarno. Which would make more sense, since they were all part of the Cicero/Melrose Park crew, than a beef with D'Amico; who I believe is more aligned with the Elmwood Park crew on the North Side.
As for the crews, it's true that it was revealed during the "Family Secrets" case in 2005 that there were four crews - the Elmwood Park/North Side crew, the Grand Avenue/West Side crew, the Cicero/Melrose Park crew, and the 26th Street/South Side crew.
At least at that point, it was said that, while John DiFronzo and Joseph Andriacchi had over all oversight of the Outfit, they still maintained oversight of the Elmwood Park/North Side crew; which they did through Peter DiFronzo and Rudy Fratto.
It was said Joey Lombardo had continued to maintain over all oversight of the Grand Avenue/West Side crew; through Anthony Centracchio until he died in 2001. More recently there were rumors that Joe Cullotta was running the crew. And now the latest rumor is that Albert Vena is.
It was said that Jimmy Marcello had run the Cicero/Melrose Park crew before he became part of the administration. Afterward you had Tony Chiarmonti and Tony Zizzo in the mix. And later Mike Sarno, who apparently eventually became the new Outfit boss (at least one of them) after Marcello was behind bars.
It's been long said that the Carusos continue to run the 26th Street/South Side crew.
To add to the information that has come in recent years, a few years ago it was reported that the Outfit was being run in "northern and southern sections." And that, while Joseph Andriacchi oversaw the north, Al Tornebene oversaw the south. There really wasn't any explanation beyond that. Was it something similar to having 2 area bosses, much the same way there used to be 3 area bosses? Did the north side area, under Andriacchi, consists of the Elmwood Park and Grand Avenue crews? And did the south side area, under Tornebene, consist of the Melrose Park and 26th Street crews? One can only guess.
To add to the confusion, another article around the same time said that Andriacchi had oversight of all four crews. And he was sort of the underboss or street boss for DiFronzo.
Beyond that, one FBI official made a statement in a more recent article that the Outfit was down to "two or three crews." But he also didn't expound beyond that.
Needless to say, it's often hard to add everything up because of the conflicting information. But, in my opinion, it wouldn't surprise me if we were now looking at 2 or 3 crews. DiFronzo, Andriacchi, and the rest of the Elmwood Park crew are reported to be involved more in legit businesses and not so much in the street rackets. Meanwhile, you have the Melrose Park and 26th Street crew who are more into the gambling, loansharking, burglary rings, etc. And, after former Melrose Park crew boss, Jimmy Marcello, eventually became the boss; Sarno then followed him into that position. And it was reported that the Carusos were paying tribute to Sarno. Meanwhile, you don't hear a lot coming from the Grand Avenue besides internet rumor.