OK, so maybe that took a little more than a week, but I’m just about to wrap it up and have a few additional notes to add.
On the whole, the migration went as described. I started by installing SQL Server and SQL Management Studio, and restored a backup of the BESReporting database from the source server.
In SQL, I needed to modify the Login for “LocalSystem” to grant the “db_owner” role to the restored copy of BESReporting.
I created the directories for ReportFiles and ArchiveData and copied the content from the source server. Then I installed BES Web Reports and it went without a hitch. After the initial install I had to log on, and in the Datasource tab I had to enter a Master Operator credential to my BES Server for the one-time configuration.
One gotcha is that after the initial install, I was unable to logon with any LDAP accounts. My original BES Web Reports server was first installed with BES 8.x, and used the old-style LDAP authentication. The new Web Reports did not have that flag set, and was trying to use the “newer” LDAP configuration, but my existing LDAP source did not have a group mapped to a Web Reports role, so none of them could log on. https://www.ibm.com/support/knowledgecenter/SSQL82_9.5.0/com.ibm.bigfix.doc/Platform/Web_Reports/c_post_LDAP_upgrade_steps.html#c_upgrade_tem_web_reports
I logged in with the built-in operator account and assigned an LDAP group to a Web Reports role, problem solved. In the meantime though the lack of a role stopped all of the scheduled reports created by those users, and they had to be re-enabled individually.
I also found that, of all things, the Outbound Mail Server was not set. I had to configure that through Administration->Address Book->Email SMTP Server.