Keeping it simple

I don't think they would split up Panarin and Stome. Also if Blais and Reaves are in the lineup, I think they will both be on the 4th line together

Because?

LaFreniere is not ready to bump Kreider off the top line. Strome should stay with the Breadman and it would be interesting to see if Kravtsov would be better on the kid line or up on 2nd. Blais could provide some balance on the 3rd; and lastly, Barron should get the shot at 4C and Gauthier should split time with Reaves

One thing Gallant likes in his lines is balance. Your fourth line assessment aside, both he and Drury will likely want to press Chytil and Kravtsov into second line duty, using their size, speed and youth with Panarin; simultaneously, he will tap into the aggressive style that LaFreniere showed in junior hockey, that made him an all around talent. Placing him with Zibanejad and Kakko on top line minutes, means he can parachute back if the time is too much for him, or he simply fails.

Kreider and Strome can be effective on a third line, where their speed can replicate Stephenson and Tuch in Vegas; while Blais offers size and a great shot given his propensity to be a netfront presence.