Resolve Guests, Contacts and Mail Users conflicts
Currently if you want a contact (to add to Distribution Lists) a mail user (to allow the external user to have an alias in this tenant) and a guest (to allow SP/Teams access from their external account, you have to create these in the right order, i.e. contact then guest then mail user.
Whilst I understand the complexity at the back end, we really should remove this conflicting between guests and other object types, and the service should resolve those issues itself.
It is clearly acceptable to have all three objects, so it should allow them to be created in any order to avoid a massive headache to customers.
This is particularly relevant for mergers, acquisitions and divestitures where guests currently become a total nightmare to manage