Cutover migration with already setup Azure AD and SSO

Hey JakeJoint ,

There are a few challenges here, to answer your questions first:

1. Disabling Dirsync will not delete the users, the users will be converted to in cloud with same password. However, if you are planning to perform a cutover migration, having users with same domain in office 365 would cause issues. Cutover migration process basically creates the users on its own in office 365, if the same users are present in office 365 cutover migration will fail.

2. Cutover migration requires dirsync to be disabled and there should not be any users present in office 365, so you will have to disable dirsync and delete in-cloud the users from office 365 ( if they are provisioned with same upn).

3. It is not a requirement to have exchange server on-premises after migration, you manage user attributes in a synced environment using active directory users and computers.

All things considered is there any specific reason you are opting for cutover migration  ? a hybrid migration will be best with your current environment.