Joseph–I changed the timeline settings, which may have accomplished something but the render window still limited my options to 23.98 and 24. I think, like Rohit implied, once a project is in motion it may not be possible to alter it in the way I needed to in this instance.
It had been 29.97, I changed it to 24, and needed it back at 29.97. It’s for broadcast in Brazil–I assume 29.97 is their thing, or the filmmaker just chose that for his own reasons. Apple Cinema Tools allowed me to change it to 29.97, and the audio was literally only one frame out of sync. Problem solved for now–better preparation will solve the problem in the future.