Decommission your on-premises Exchange 2010 server in a hybrid deployment

Scenario two

Issue: My organization has been running in a hybrid configuration for about a year now and have finally moved my last mailbox to the cloud. I plan to keep Active Directory Federation Services (AD FS) for user authentication of my Exchange Online mailboxes. (This scenario would apply to any customer that is planning on keeping directory synchronization).

Solution: Since the customer is planning on keeping AD FS, they will also have to keep directory synchronization since it is a prerequisite. Because of that, they cannot fully remove the Exchange servers from the on-premises environment. However, they can decommission most of the Exchange servers, but leave a couple of servers behind for user management. Keep in mind that the servers that are left running can be run on virtual machines since the workload is almost completely shifted to Exchange Online.

So if we need to keep one Exchange 2016 server. After the Server install, I have noticed that may ask to update the  Service SCP on Windows 2016 server and configure Virtual directory URL etc etc,

But  this  https://docs.microsoft.com/en-us/exchange/decommission-on-premises-exchange

say SCP set to null and remove the hybrid configuration?

We had few Exchange 2016 servers and they all were decommissioned. So installing the new Exchange 2016 need schema update and domain update? 

We can see some send and receive connectors and mail flow through this server. 

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