We are working on AD separation project wherein we will going to have new domain setup and then migrate O365 services (user mailboxes and SharePoint ) for few users from existing tenant to new O365 tenant. Messaging environment is in hybrid with on premise exchange in existing domain.
Tools we are considering are : ADMT and BitTitan for Tenant to Tenant. Though I have below draft but identified few below GAPS . Need inputs .
I understand the below high level steps :
1. setup new domain . Migrate users from existing to new domain .
2. Setup Azure AD connect and synch users to new O365 tenant
3. Migrate O365 user mailboxes from existing tenant to new O365 Tenant.
GAP - Since mailbox migration will take sometime to move to new tenant. What will happen to email access during this time?
How do we deal with free/busy between the scenario between users in 2 seprate domins with seprate O365 tenant?
4. Migrate SP to new O365 SP
Objective is to avoid disruption to users and making migration error free.
Any pointers/or if have any document /article link from MS that would talk about the right sequencing for such migrations will help.