This is my stab at the Omerta timeline -


October 19th - Don Dominic calls a sit-down of the Three Families to be held at the Ultra Luxe. Dominic, with the support of Marjorie, accuses Swank of breaking key tenets of The Contract. Swank denies all accusations and abruptly leaves the meeting without further elaboration. 

October 25th - The Omerta Family begins a  buildup of weapons and illicitly purchased military hardware, increasing their production of small arms across their compounds in Outer Vegas. These weapons are secretly shipped to the Strip. Omerta-affiliated thugs across Vegas are noticeably better armed. Iron Forester Mercs begin actively patrolling Omerta controlled areas of Vegas. 

October 30th - Don Dominic Omerta and Marjorie of the White Gloves are married in an overly-elaborate ceremony at the Ultra Luxe. Various underworld figures linked to the Don from across the Southwest attend in a notable gathering of the whos-who of post-war organized crime. The White Gloves and Omerta Families are formerly united by marriage ties. None of the Chairmen attend, nor are they invited. 

November 1st - A gunfight erupts between several armed groups in Freeside. The brief but violent skirmish results in 18 dead. Rampant fear and speculation regarding further escalation of the Families’ conflict spreads throughout the city. The Heads of the Three Families all publicly deny any involvement and claim this was an unrelated gang conflict. 

November 4th - The Flooding prompts the Omertas to evacuate several of their safehouses in Outer Vegas. In an unexpected move, Dominic publicly announces that the Omertas and White Gloves will be assisting the people of Outer Vegas and Freeside with relief and recovery efforts. Thousands of caps are spent on hiring laborers and opening Omerta-run shelters and soup kitchens to provide aid. The White Gloves agree to open up their considerable food larders to provide adequate stocks to these locations. The Omertas supply a number of makeshift hospitals in the area with medical chems. 

November 14th - Legion activity across the Colorado prompts an unusually unified response from the Three Families, who issue summons to the NCR ambassador for clarification on the situation.