The general consensus seems to be that it was a Commission sanctioned hit carried out by Bonanno members. Presumably Dellacroce was their liaise with the Commission.
Yes. Bonannos didn't have a seat on the Commission at that time.
Neil and Galante hated eachother from what I read so obviously he knew about the plot and it was approved by the commission who felt that galante was too much of a loose cannon
Lots of people hated Galante, and for good reason. But, the reason the Commission sanctioned the hit was because Galante had set up a profitable heroin pipeline from Sicily--and wasn't sharing it with the other families. You can never go wrong in Mob hits by following the money.