How are you going to mount the CP? If you screw it on a box/ some battens, those will take up some space. Because of that, the spinner won't fit in that position, and the upper buttons probably won't, too.
Also you have to consider that every compoent takes up more space underneath the CP than above. For the buttons it's the micro scwitches and the wiring, for everything else it's the wiring. If you put the buttons so close together, you are going to have fun trying to align the switches and wiring them together.
I suggest to use of scrap piece of wood, drill all the holes and actually put all the components in or at least cut holes in the cardboard mockup and put everything in (don't forget the space that your mounting method will eat up!). Try to mockup some of the wiring, too, as this also uses up some space.
Last but not least, you have to put the encoder somewhere, too.