Better at what? Cardio?
Same number of points in less time, and less opportunity, Lorentz has better possession numbers, bigger, far more physical (62 hits to 8)... Lorentz is exactly what you want on a checking, cycle, forechecking 4th line. Yes, Lorentz is a good fourth liner... and he is playing on the fourth line, where he is good at his role.
How are you determining Dewar is better defensively? We give up less goals with Lorentz than Dewar. Lorentz expected goals is better... And.. Dewar on ice goals for... .ZERO.
Holmberg isn't really a fourth line player... he's a third line guy, who isn't good enough for the third line... everyone needs a role, and unfortunately he isn't good enough at it, and likely isn't on the squad, or is the 13th guy.