Procedure to remove mailbox server role from Exchange 2010

Looking for some expert advise and validation.

I have 3 Exchange 2010 servers with mailbox role in a DAG. Each Exchange server has a default Mailbox {Mailbox Database NNNNNN} and a copy of the user database. I want to remove the mailbox role from Exchange Server1 (of 3) which was the first Exchange 2010 server that was installed. I assume this process will do it:

1. Assure  The default Mailbox NNNN has not user mailboxes

2. Move arbitration mailboxes to the mailbox database that has the user mailboxes (as this is HA in the cluster)

3. Remove default Mailbox NNNNN database from Exchange Server1

4. Remoce database copy of users mailbox Database from Exchange Server1

5. Remove user mailbox database from Exchange Server1

6. Remove Exchange Server1 from DAG

7. Uninstall the mailbox server role with installation maintenance

done

Questions:

A. Are the above steps correct or any modifcations needed?

B. Should the arbitration mialboxes reside in the HA user mailbox database (I have only 1  currently) or should I move it to a seperate mailboxdatabase?

Thanks for any advise.