Nah, George is done. IIRC, he had some loose connects to the FSPDU, but was a bit player before his son embarked on his crusade.
Fucking Arico...wasn't he connected with Dino Dibra, and by extension at the time, the Sunshine Crew and Williams himself? I know he was named as a suspect in the Mladenich hit, and that Williams was alleged to have been planning on talking about it, which may have implicated him (Arico). I also recently read some articles that named Arico as a suspect in the murder, and understand that Johnson and the as yet unnamed inmate present were associates of Aricos.
I call bullshit on the Gatto connection RE Carl Williams murder. Source for that? As far as I understand, a former Gatto associate claims that Arico communicated details of the murder to Gatto, and that Gatto may have known that Williams might be killed, but no indication of a conspiracy to murder on Gatto's part, or a required "permission", so to speak, sought from him. It seems pretty well established that Johnson murdered him on account of the revelations published in the Sun that very same day, and potential further information Williams was going to supply to police (he was known as a dog/rat by that time). I can't answer whether or not Arico was indeed responsible for the order, but his history indicates he has both the clout and connections to be a viable suspect. I mean, there's obviously a reason police are looking at him so hard (and multiple sources state that he was amongst the first to know of Williams death). It's a bit of a cluster-fuck at present. We had to wait years just for Goussis, The Duke and Johnson's names to be released. The next few years will likely see more light shed on the matter.

...fuck, sorry for the wall'o'text. FWIW, I found Aricos current lawyers surname interesting, considering its shared by a prominent victim of the Gangland War who did have established connections to some Calabrian families.