When I attempt to create or convert a PDF in Acrobat DC I get the error "Your request could not be completed. Adobe Acrobat DC license has either expired or not been activated." This occurs even though Acrobat has been installed via a Customization W

Uninstall Adobe Creative Cloud and then restart your computer, that should solve the problem.

In the Customization Wizard, you need to enter the Acrobat serial number and generate an offline exception. Then you should output the resulting mst file along with the msi using the command line

msiexec /i <path\AcroPro.msi> TRANSFORMS="AcroPro.mst"

http://www.adobe.com/devnet-docs/acrobatetk/tools/AdminGuide/cmdline.html

If you have already done this then you can use tools such as APTEE to serialize Acrobat.