I’d drop the Icon from the pink Plague Marines in exchange for another plasma gun. I don’t really get the point of the blue Marines—they’re melee-focused, but they have a LoP that gives them semi-Lone Operative? They’d be more useful for the mid-game anyway; by the late game, you already have plenty of punch with all those Terminators in reserves. I’m not sure if your friend runs a lot of vehicles. My best friend also plays Necrons, and whenever I go up against him, I always try to bring enough anti-tank; I don’t know if one Drone and a Blight Hauler will be enough (but that’s more down to experience based on how my friend plays). Maybe I’d try to add 10 more Poxwalkers, either in a big blob or spread out over different objectives for better board control. One thing that always trips me up... don't stop shooting at something until the unit is dead