wrench1, thank you for all the clarifications.
Part of my interest relates to the ongoing Congressional agitation (to put it politely) around matters, and/or issues, concerning modifying, reforming, rebuilding/starting over, the ODA process. While the FAA as regulator deals with its APA obligations (as you point out) the Congress will try to keep up, and also try to envision the next set of problems in the future and define via legislation what could be successful or effective in keeping those problems from occurring, or minimizing them. The various admin actions will get a lot of airtime as part of that . . . and as part of the international commercial issues bound to arise or recur.
At the same time, to anticipate a shortage, let alone absence, of grandstanders on Capitol Hill - and among aviation interest groups and lobbies - would be a bit disappointing. Meaning, to understand separation between AD/NPRM under administrative law, and the comparatively only policy-making admin maneuvers, is a big point.