To add an all off button, you will need to right-click that button in the Project Navigation panel and select Macro -> All Off’. That will automatically add all actions needed to switch off all dimmers and relays in your project. If you want you can remove actions that are not desired.
A module’s name is only stored inside your project file, not inside the module. So if you read in your module, the module names will never get overwritten since there is nothing to overwrite them with.
Well, you can cheat 
You can add a pushbutton module to your project that doesn’t exist Project → Add Module. Then program one of its pushbuttons as an all on or all off. As a last step, configure your comfort remote to simulate that particular pushbutton.
The unique identifier for a module is its address. The module name is not that important since you will always be interacting with a channel, not with a module. For example, you will switch on the first relay of a module which is called ‘Kitchen lights’. Eg. Switch kitchen lights ON/OFF