Meant to get a picture last night and forgot, but to answer your questions, it's a symmetrical spindle so flipping it shouldn't help. The cable tension is correct, and it won't shift because the derailleur doesn't physically extend out far enough to move the chain. The cage barely hits the chain but doesn't move it.

I forgot to mention, it's a braze on mount and I've got an 8 speed cassette on the rear.