I would like to have a Central Database object that acts as a central API to the actual camera and to all the GUI elements that visualize said parameters.

I want to have Setters and Getters for an arbitrary number of parameters (and types: integer, float, Strings, etc.) which could be identified with a unique string name.

CentralDB->GetParameter("ExposureTime");

menuItems or Screens should be able to subscribe/attach to any parameter and with a handler(functionpointer) that is called when the value changes update their desired GUI elements.
E.g in pseudo C++ code:

MyGUI()
{
    CentralDB->subscribe("ExposureTime", &UpdateMyGUI);
}

void UpdateMyGUI(sender*)
{
    _expTime = sender->GetParameter();
}

CDC Messages received by the Remote from the camera should trigger such a value change as well.

https://sourcemaking.com/design_patterns/observer