I ordered the 3 gang switch assembly and here is what I've learned. The switch assembly contains a circuit board that controls everything. Each switch assemble only has 4 pins that go to the harness, although there are 6 wires on the harness. The only difference between each circuit board is the addition of some chips. In the pic, the 2 gang is on top, the 3 gang is on bottom.
I'm looking into the wires going to the harness now to identify what they do and what each pin controls.
As for the individual switches on the assembly, the blanks are all able to be made into working switches by shaving off the stops on the back side. You would have to install a switch as shown in the previous posted link. The backlighting for the stock switches is thanks to an LED on the circuit board and the switch left unpainted on the interior. The front symbology is just unpainted white surface allowing the light to shine through. The plastic block that is between the switch cap and the assembly is what presses against the membrane that contacts the circuit board, it rebounds when you take your finger off the switch and the switch pops back out. The hazard switch is the only on that has a clip that connects to the switch installed on the circuit board, keeping it depressed when you remove your finger.
I'll let you know if I figure anything out, but it's looking like most likely I'll have to go the route of installing my own switch behind the cap with wires installed through the assembly housing. But hey, at least I have a button with plexi already installed and an unpainted interior for backlighting capability.