For survival, a nice team to use is Junior (Shank) and Defender (Shank). Have Defender with the sledgehammer and shotgun patrol the bottom part of the map, while Junior with the pistols and chainsaw patrols the top part of the map. Both have extremely fast bomb disarming speed. Defender specializes in melee weapons (that aren't the shanks) and can buy turrets and shop weapons for a really cheap price, being able to crowd control large groups of enemies and dispatch strong and fat enemies easily. Junior specializes in pick up damage, but his focus is bombers and anyone with a gun.