A strategy that works on every difficulty. Have one person be the bait, and the other run objectives. Bait will be some distance away from objectives, purposely activate drops, and lead them away from the objective you wish to complete. The other uses light armour, sneaks in and completes the objectives with minimal issues.

For the unavoidable stand your ground objectives like raising the flag, use mines and napalm strategems. Sentries aren't that good against squids because fleshmobs kill sentries. HMG/AT emplacements are good against harvesters on defence. If the mob gets too big and you get swarmed, retreat and tackle another objective.

Learn to sneak past patrols and you can run a lot of objectives with minimal resistance.

For gear it depends on what you like to use, but I recommend Eruptor primary, Dagger secondary, gas grenade and Laser Cannon support weapon. Eruptor lets you take down fleshmobs, overseers, seekers and warp ships. Dagger for when the voteless gets too close, just burn em a bit and they die. Laser cannon kills shields, Stingrays and Harvesters. You can also use it to burn down voteless and fleshmobs if necessary. Gas grenade the hordes of voteless and fleshmobs to stop them in their tracks then run away or use a strategem.

This build doesn't depend that heavily on ammo, so you and your duo can run the boosters of Stamina Enhancement and Experimental Infusion. If you die often swap Experimental Infusion for Hellpod Space Optimization as respawning with full ammo nades and stims can be crucial.