It was Edmundson's second goal of the season, and his first since January 23 against the Canucks, snapping a 24-game goal drought.
Weber picked up his second assist of the night, while Tatar was credited with the other helper to reach the 20-point plateau.
That's the way things stood after 40 minutes. The Canadiens also held a 22-12 advantage in shots.
Vancouver struck again with 22 seconds elapsed in the third period to make it 3-3.
Captain Bo Horvat deflected a point shot by defenseman Quinn Hughes for his 14th goal of the season.