First of all, you need to make sure your CUCM version supports both UCCX 7 and 8. Check the compatibility guide for that one.
You don't need to reinstall CAD, as it has a feature built in to auto upgrade. The only required action would be to point CAD at the new server. There are a couple different ways to tackle this, so look into either running postinstall.exe on each client and typing the new ip address, or modifying the registry of each client (which is what postinstall.exe does).
The license you listed will upgrade an existing UCCX Enhanced High Availability cluster from 7 to 8. I hope that is what you have, versus Premium, etc. As with any upgrade you would apply the license files from your 7x system, along with the new 8x license to the new 8x server. Granted you are doing a fresh install, but this will still work. I have done it several times. Simply zip your .lic files (no folder) and upload the zip when you are going through the license upload piece of the install.
Build your triggers and cti ports on the new system with new numbers, then swing your translation patterns at the moment you want to convert.
Give your app users new names. If you haven't done so in the past, now is a good time to rename them something meaningful: uccx_rmcm, etc