OK, this is weird: On my home machine which I just upgraded to F26 from F25, I didn't need the fix from post #16. I tried running Acrobat Reader before making the changes, and it worked perfectly, including printing:
I suspect that in the time since F26 was released, maybe some GTK+ or other library was updated that fixed the problem. Regardless, I'm happy that on my home F26 system Acrobat Reader runs just like before in F25, without any hacks. Yay!