you could try switching back to stick but leave your tig torch attached and put a piece of stick rod in place of your tungsten. that would test the path of power.
foot pedal should not be needed. with dial turned to tig and leads reversed from stick it should work. lift arc takes a solid touch sometimes to get started.
i just recently fixed a fuel grinder that sounded to have failed in the same fashion. the bearing went out on the battery side of the motor. it is mounted in plastic that i believe made it smoke when it failed.
It looks like a one piece ferrule to me. Kind of like a parker 24 degree flareless fitting. mcmaster carries some of them.
Are the threads on male body 7/8" 14tpi?
I have done one on a concrete basement wall with a Husqvarna cut and break saw. it cuts a few inches deep and then you break the piece out and cut again. it can all be cut from outside to help with clean-up. it took a half day rental to cut a 3' by 4' opening.