Splitting shared Apple ID
Apps:
All Apps that are eligible for family sharing will be available on a new AppleID that is added to Family Sharing.
Keep in mind that In-App purchases are not shared. More detailed info is available in the Apple Support Article.
A desktop computer (preferably a Mac) would probably be the easiest way to properly distribute the content. Set up both the new and old AppleID and then use the appropriate Apps to move/copy the calendars/events/contacts/...