Assigning numbers to lines isn't how this coaching staff operates. Tortorella may have had clear cut 1-2-3-4 and used only two of them, but that isn't what Vigneault and Arniel do.
In the most critical moments of the playoffs Vigneault rolled all of his lines. And the reason he was able to do that was he built each unit's confidence over the season by giving all of them ice time, and sticking with players through their struggles, Pouliot and Zuccarello specifically.
Fact is, there are units and pairs that have proven chemistry, and it is highly unlikely that the coaching staff will be looking to dismantle the remaining chemistry after the exodus of players via free agency that just occured at the start of this month.
There are at least 5 new forwards that will be regulars, including the 13th, and 2 new defensemen, including the 7th.
Carl Hagelin played on what some would label the "2nd line" all season, while Brassard and Zuccarello played on the "3rd line". This team has 5 "top 6" wingers.
There are no lines 1-2-3-4 with this coaching staff. There are 4 lines and they all play. Plain and simple. The only positions that have a huge disparity in ice time between units are the defense and goaltending, where there is a clear cut #1 and #2 defenseman and a clear cut #1 goaltender. Otherwise there is going to be very little disparity. That was a strength and a reason we got as far as we did.