AM-HMNG-VA: Zero currency SKU needs to be purchased.
Once the VM image is spun up and working, it needs licenses, and configuration and lastly the devices need pointed to it.
Customer should be able to backup their HMOL account/configuration.
On the VM HM, you should be able to restore the above backup file to retain all the exact configuration.
Lastly on the HMOL side of things, you should be able to select all of the gear and modify it, and under the Credentials section, you can alter the primary/backup HM. Put in the new IP of the VM HM and push that out. That should change the gears CAPWAP server IP. The gear will come in as unconfigured. Apply the configuration to the gear (should all be identical), and push out. Reboot most likely needs to happen since its technically a new HM/Network Policy. Once gear comes back up, things should be working as intended.
The above is a real rough draft, but I believe it should cover everything needed to move gear...
Make sure that you have all your settings documented before you attempt your migration. Because not every setting gets migrated. The majority of your stuff gets migrated, but there will still be a few things that do not. You will need to go back in and double-check everything. And your database size will need to be under 1 GB. I'm in the middle of migrating my on-prem HM to a new, beefier VM and have discovered some of these issues.