Just to make everyone aware if you beat this on Legendary co-op system link, you will not receive the Mark VI armor.
If there is any way to unlock it, maybe if Waypoint mods can look up me and 3 buddies achievements and manually unlock it (if possible), it’d be greatly appreciated. The 4 gamertags associated with this Legendary run are Nile528 (me), Kutak, Lucknine, and Locobullet1987. All have beaten it and have the associated achievements to back it up.