CrossRoads, I have made a few modifications to your wiring diagram, to make it more understandable for amateurs like myself and to be sure that I have understood things well. I hope you don't mind.
The information I have added:
1. The polarity of the LEDs
2. The value of the resistors
3. The value of the capacitors
4. The type of the MOSFETs and which of their legs goes where
5. The connections between the Arduino and the shift registers
I have removed all the additional circuitry that was around the Arduino or other micro controller on the other pins because I thought that it's not needed. In other words the only pins of the Arduino that need to be connected to anything are D10/SS, D11/MOSI, D13/SCK and GND. I hope I was not wrong...