Hmmm... everything else in CC is installing and licensing without issue, correct? OK, then let's try and get forward progress with a workaround. It sounds like you are installing other CC applications. If that is the case, then try this process as a test on a test machine environment to make sure it will work for you.
1. Download the Continuous Acrobat installer.
2. Expand the compressed installer to it's components to a location of your choosing.
3. Download and install the Adobe Customization Wizard DC.
4. Launch the Adobe Customization Wizard DC.
5. Navigate to the MSI file in the Acrobat folder and open it.
6. You can use the CC Serial number in the Adobe Customization Wizard DC and use the Grant Offline Exception.
7. You can check the Accept EULA box here too.
8. If you are turning OFF the Online Services and Sign-In make those changes and any other customizations that you want/need in the Adobe Customization Wizard DC associated panels.
9. Then build your installation command line instruction making sure to include the MST file (e.g. AcroPro.mst ) that is built by the Adobe Customization Wizard DC for the install.
An very basic example would be something like this:
msiexec.exe /i AcroPro.msi TRANSFORMS="AcroPro.mst" /qn
The ETK has a much more complete/complex example that is used for the Acrobat XI install.
11. Launch Acrobat DC
12. Are you still getting the prompt to Sign-In and Activate?