This seems to be the issue...
airmon-ng is now actually airmon-zc with a namechange. if you do 'sudo airmon-c start wlan0' you go into wlan0mon mode instead of mon0.
Also, seemingly due to the new wps exploit avenue, the reaver that is being used is actually the fork t6x, which has had pixiewps functionality written into it, as does the wash it comes with. I would bet if one used airmon-zc with that reaver fork correctly installed, everything would work just fine. Whether there are any dependency issues with BackBox and those new scripts, I don't know as I haven't gone so far as to try fully upgrading to that fork and running it.
I know it doesn't fix anything, but at least it's an answer as to why wash isnt working with a probable (IMHO) solution.