Along with Jesper's suggestion, it seems like your moving everything to a COLO.
That being said, a new LDAP database, SQL server and Exchange server will be a large number of GUIDS changes. So do an install, then import the orgainization.
I would do a test migration before I moved everything to the new environment.
Check to see which accounts have deployment administration rights.
Recreate those accounts in the test environment for migration and the new environment.
Those accounts have the right to migrate an organization into a new environment.
There have not been a few, hard to explain errors in migrations so I strongly recommend a test migration. Also be aware of IP versions, HBA adaptor drivers and Switch IOS versions.
They could cause issues with packet sizes.
I've not seen much documentation regarding these pitfals we see in the field, so it's best to plan for them and know that beyond the software level the "Road" may be the problem.
Hope all this helps.
Curtis J Spanburgh