I'm putting this up as a peacekeeper. I hope one day I'll fill it in better, but if you are trying to migrate from a shared Apple ID to each family member having only one Apple ID for both iCloud services and media then you will welcome any information.
First, see my prior post. I'll continue with this convention:
Let's say my iCloud Apple ID was "Sam" and my Media Apple ID was "Linda". So my device Apple ID configuration was Sam/Linda. After the change it was Sam/Sam.
I think the migration will more or less work. This is what I did so far, omitting errors and redirections:
- Let my Apple Music subscription lapse and cleaned up other subscriptions. These were owned by "Linda".
- Subscribed to Apple Music one day after the lapse using Sam. I'd seen hints Apple keeps iCloud media data (playlists) around for at least 1 month post lapse of subscriptions. I can confirm they last at least 1 day.
- Changed my devices to be Sam/Sam (maybe this would best be done later)
- In iCloud Family Sharing settings opened settings for Sam. Even though my device might be Sam/Sam when I inspected details on my Family Organizer Apple ID I could see shared access was mediated by Linda. I changed that to Sam in Family Sharing.
- Changes to media rights seem to take time to be effective. After starting a subscription give it at least 30-60 minutes.
- iTunes classic allowed import/export of XML playlist files. These are useless. The key identifier is the track ID so they only have meaning for the Library they came from.
- Sharing a playlist by URL from Monterey worked -- but not at first. It got hung up in the subscription translation.
- Even after family members had renewed subscription access they needed to do something to get Apple Music.app to synchronize. Sometimes this was clicking on the sign-up add for Apple Music then choosing the subtle link for "already have a subscription". Sometimes shutting down and restarting. Sometimes looking at Music.app preferences and turning on iCloud library synch. (Sorry, there were so many issues!)
- There are two kinds of Playlists - "Apple Music Playlists" and traditional iTunes/Music playlists. I think when you migrate an old iTunes library to Monterey the app turns legacy playlists into Apple Music Playlists. Not 100% sure about this.
- I'm not gonna talk about this more, but I'm still running iTunes on Mojave and I'm amazed it works at all. It more or less survived the process. I have future work to do around migrating things out of iTunes on Mojave. (That machine will be an Aperture machine until I migrate that -- an even greater challenge. Then it will likely be replaced.
- Post migration it's not clear how to identify what a Family Member purchased from the days of the shared Apple ID. Apple suggests going to reportaproblem.apple.com; it only goes back 90 days though. Before doing the Apple ID migration the Family Organizer view had data broken down by family member, but after the migration that was very limited.