Depends on your hubs - if your original hub is a C-5 you could just leave the Zigbee devices on it. The ZB radio has not changed on the C-7.
Zigbee is the easiest to migrate because it does not have an internal DB stored on / tied to the radio chipset like Z-Wave. Basically backup/restore to a new hub then remove non-ZB devices and put new hub into pairing mode and go around and put each device into pairing mode. Make sure the original is offline when you do this though.
For the Z-Wave devices use the migration services (may have to remove any included Zigbee devices running on the other hub) or the following: