I'd trade Petry, Shaw, plus any spare part on LD not named Mete to upgrade the left D with a young LHD no older than 25. I'd throw in our extra 2nd round pick, if needed, depending on the return at LD.
I like your lineup, but there's no way a line of Lehkonen - KK - Suzuki is ready to assume first line duties next season. Knowing Ju-jube, The Danault line, with Tatar and Gallagher, gets 1st line minutes in a shutdown role. Then the KK line and the Poehling line get even minutes as the 2nd and 3rd lines. I'd go with a 4th line of Byron - Evans - Armia and roll out Agostino as the 13th forward.
IMO, that leaves MON with three 2nd lines and a 3rd line. There,s scoring potential throughout the lineup and two-way responsibility as well.
Better than the Lafleur lament about having four 4th lines.
Tatar - Danault - Gallagher
Domi - Poehling - Drouin
Lehkonen - kotkaniemi - Suzuki
Byron - Evans - Armia
Agostino