For the fastest possible migration experience, if you do NOT need your CDR/CEL (calls) history and Recordings migrated over, you may DEselect the “CDR Reports,” “Call Event Logging,” and “Recordings” modules in the Modules list. This will greatly reduce the backup file size AND greatly reduce the Restore process time on the new instance. We have seen CDR/CEL restorations from older/larger instances take HOURS to complete. You always have the option to export a backup of just the CDR/CEL and Call Recordings from the old instance to later import into a SQL and/or File server of your choice if you need archival retention of that call data.
Deployment ID in the PBXs > FreePBX section and click the blue view/eyeball button on the right. Your Deployment ID can be found on original instance under Admin > System Admin > Activation 

Licenses tab at the top and scroll all the way to the bottom and locate the Reset Hardware Lock button (yellow). Click this to release the Deployment ID for re-use. This will NOT immediately invalidate the old instance activation, giving you a day or more to complete the switchover with both instances activated.

Note that rebooting the original instance after this point will force a release of the activation on that machine!