Yes, you can change the hostname of Voice devices. Only changing CallManager hostname is not suppported. So, once you have changed the hostname on the Router, VG224, you will have to change the same on CallManager as well and then reset the devices.
Impact: Once the router name is changed, it will unregister itself from CM and cannot be used until the same in changed on CM and reset, re-registered.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...