Office 365 Group structure and Migration

[kwesterink]

Dear Readers,  

My employer gave me the assignment to use just Microsoft Teams within Office 365. So we enabled AD sync, bought licenses and set up Teams "Lite" Basically chat and that's it. This means we did not migrate Exchange or any other service yet.  It's just for our internal organization, no guest or externals are allowed yet. From that point they want to extend step by step to full Office 365. 

I am aware of Office 365 groups and that you can upgrade on prem hybrid Distribution Lists to Office 365 groups.  

Currently we have our organization divided in teams, they are part of on prem security groups and on prem distribution groups. Can anyone advise me into creating Office 365 groups to reach this goal without breaking exchange, teams and distribution lists after migrating everything to 365. 

My main headache is that when you create a team you automatically get an email with it. What if I create an office 365 team HR with e-mail hr@domainname.tld  and then migrate exchange to 365 with team HR it's DL with e-mail hr@domainname.tld

How can I avoid conflicts and seamlessly merge them.

[#2]

one option is to enable automatic naming conventions so that when people create Teams, it appends "Teams_" to the front of whatever name they use, so that it could not conflict with the groups on-premises.
https://docs.microsoft.com/en-us/azure/active-directory/users-groups-roles/groups-naming-policy
Another option is to restrict Teams creation to only Exchange admins who can verify that the group gets created without conflicting with a group on-premises.
https://docs.microsoft.com/en-us/microsoft-365/admin/create-groups/manage-creation-of-groups?view=o3...