Okay, so formatting isn't nearly as traumatizing as I thought it would be. I've gotten the preliminary formatting done for the stories I have final versions of. Which, granted, is only four out of eleven, and it doesn't include any illustrations, but at least now I have a handle on the process.
And, since we have time this year, I can export the individual .INDD files to .PDF files and send them to the authors to glance over, just to make sure I'm not overlooking some of the finer points.
So, my outlook on the whole process is definitely more positive than it was. Now, if I can avoid any major crisis I'll be in good shape.