A -
B - Don't snip, T into this one. It hooks into the hatch release and brake interlock etc. But ya, sounds like you got this one.
C - Brown wire from the fuse labeled TURN B/U (Back Up) feeds pin C. Hook C up to the fuse, not the other wire.
D - Run the Light Green wire from the shifter to the reverse lights Light Green wire. Connector C400 is a 6 pin connector near the driver rear tail light. It feeds the rear lighting. Obviously the reverse light wire is here. You can probably trace it back a bit in the car and tap into it. Got it?
E - Yeah, you can just connect it to the CSS wire.
F - Sorry I was tailing off on the idea of deleting VATS. Ignore all that and the color is Dark Green, its the other wire on the CSS. Yes, connect that wire to the shifter wire.
We good or want some ms paint brah???