Just thought I would offer advice, on the new DLC achievements:
One for All - With any of the additional characters, perform 20 ‘Revive’ actions.
Best team mode for this is Wolfpack
Wolves for Lambs - Complete a Wolfpack multiplayer session on any of the additional maps.
Don't know whether it's confirmed but do you need to complete Sequence 25, if so forget randoms you won't do it, either do it solo (depends on what level you are for abilties, perks, kill steaks for later sequences for maximum points) or do it with friends.
Stubborn Stunner - Stun 3 pursuers without dying, playing with any of the additional characters.
Unless you enjoy the MP and know what you are doing, then boosting is best.