Nice post. As ever the devil is in the details!
One suggestion I would make if anyone has to go through a database file move and consolidation is to double-check the storage.
If you have an underlying SAN then involving your SAN administrator can make life a lot easier. They will know what the physical storage underlying the presented drives looks like and whether it will support the IO load of the consolidation.
It may even prompt them to devot dedicated storage to SQL Server.:cool:
It's very easy to forget that there may be things outside of SQL Server that can affect the performance and effectiveness of SQL Server.