Here’s even a photo of how my cabinet looks like and how your central one would look like, too. Some actuators are FGRM-222, some are for the lights. The box is you see in the cabinet is another Pi. It’s not the Pi with the zwave controller running OH, that one’s located in a different room even on a different floor. But I could connect the relay bank and the roller shutters to it, too, if I wanted to.
By the way, I don’t have any pushbuttons for my roller shutters.
As you’re still in planning phase, spend some time on rethinking your user concept for roller shutters, light switches etc.
Personal preferences vary, but for us, for the rollershutter buttons, it turned out you don’t really need them because you can have OH operate them based on time of day or other trigger (such as if I turn on my TV).
Same as with the wiring, though. If you omit it, you need to be prepared your wife will tell you she wants them back just after you’ve finished decorating the walls 