The guy who is helping me along said this, after we realized our mistake:
"But yeah - any software you write for any arduino will work on any other one. The only thing you may have to do is change the pin numbers.
You can definitely get the functionality working for individual components, and then upgrade to a custom PCB when you integrate all of them. For example... just get one haptic feedback motor, one flex resistor, and the 3d sensing stuff. And then for the custom PCB you can toss in all 4/5 sets of motors/flex/whatever."
So I think this would be a good way to go about it while I await to find out how everything is to laid out. I want to cut down on bulk and overall size, so this may help.