OK, this is about as done as it's going to be for awhile. Kind of lost the steam to get into it any deeper as I need to start pulling components for values. I also have no plans to pull the conductive pad from the A, B, X, Y, BLK and WHT buttons (they are Analog buttons on this controller) as once that thing is peeled off it's either wrecked or a royal pain to get back on and there's nothing to see under there but traces anyway. The core of it should be pretty much all there, and if anyone sees anything wrong let me know.
NOTE: I have no idea how many revisions they went thru on this thing, and there were also knockoffs floating around of the S-controller, so this schematic only applies to the one that is shown above in the board scans here.
NOTE of interest: The Triggers and 6 Analog buttons are done thru a multiplexer (U3) since the MCU only has 6 Analog inputs, and 4 of them are used for the Sticks, so the last 2 Analog inputs read the Triggers and 6 face buttons.
https://www.acidmods.com/RDC/XBOX/S-Controller/Schematic_X00330-001_RevC_.pdf