We are currently going through that pain at the moment. So I'd like to add to your list of issues for consideration
Ensuring that the encryption certificate works for SQL, is in date and has a valid path - Requires Certificates plug-in for MMC
Ensuring that the Server service account has read permissions on the encryption certificate - ditto
Ensuring your users haven't over-written the compatible version of SQL Tools with an older, incompatible version or are just referencing one. - Check path variables and shortcut links
Getting your users to track down all those connection strings in various spreadsheets/apps and updating them to use the right drivers
Getting your BI Team to re-compile SSIS packages to be TLS 1.2 compatible
Updating SSRS to use HTTPS port, configurating all your firewalls to allow that, and all your links to use it
I have to add that creating an Extended Events session that tracks the trace event looking for function_name = SSL::Handshake helps a lot in later versions of SQL. Also having a test environment that models the infrastructure, not just individual VMs, systems or applications. Otherwise you'll find yourself testing in Production.