@renmoo Ahh funny you should ask ahahaha. I just figured it out
How can you get expendable Walther? Get 12 boxes on Co-op Survival.
How can you get the Anaconda Kukry( Perm and Expendable)? Complete Death Valley on Extreme and you have a CHANCE to get the perm or expendable.
I'll make a post on everything you can get
EDIT: Made It A.V.A Co-Op Rewards