Merge with the other section file formats
I think your alternative version makes sense. I do have one concern. The Adapt OER chapter is starting to get a little thin, and we don't have time to follow your proposed rearrangement (for this edition at least). If we move preferred formats out then we can't move anything else out of that chapter.
If we move as proposed, there will be places in the rest of the document that will need to be changed from pointing to the File Formats section to the the appendix.
Otherwise, I think it will work.