My understanding is that RAFAC Role Accounts on the @aircadets.org domain will remain, in addition to these will be personal RAFAC accounts which will have access to the various mailboxes.
MODNET is for current DII users as they move to this new system, not sure if they will still have Role Address, but looks like the change is being poorly communicated to the volunteers by the perm staff, but this may not be there fault.
As with standard DII users those migrating to MODNET will have role and personal email addresses however all emails are seen by the user in the personal mailbox, excluding any group mailboxes. There is a minor change to any DII email addresses once they are migrated to MODNET. MODNET is not accessible if you are not connected to the RLI, so the aircadets.org email system will be completely separate as with DII, this is not to say that it may also get moved to office 365 if someone decides that is a good idea.
Once the user migrates to MODNET, for an indeterminate period after migration the old address will forward to the new mailbox automatically, however the advice was that before migration an out of office notification was set to emphasize the point to anyone emailing the old address that they had now migrated.
I can’t say I’d be hopeful about updates to any aircadets.org address books, especially as the migration is on a camp by camp basis and even then not all users are capable of being migrated currently.