Finally got wheel back from Cycle Monkey (US service partner for Rohloff). The screws had indeed sheered off inside the hub. The fix was just to remove them, as I hadn't exerted any great pressure that would have damaged things.
I'm a big guy, but this still shouldn't have happened. I suspect it occurred when I hit a huge railroad-gap doing 30+ mph, fully loaded for touring. I was almost unbelieving that the bike and wheels survived, but they seemingly did. To be clear, the screws presumably sheared at this point, but they weren't forced into the hub until I attempted to use new screws later.
It's not good that this happened, but that was a very unusual circumstance, and all is now well.