CM4 - I/O, user key, etc

Hello, first off, I think this board is great- its been running flawlessly for over 5 months as my home server with an 8GB CM4 module with a 4TB RAID6 array and hot spare.
I really need to find a way of having some I/O with the CM4 though and I cant see any way on the Taco board. One for safe shutdown/UPS monitoring and one for external status/watchdog a third would be perfect.

Can anyone answer the following three questions for me:
Does the ‘User Key’ button connect with the CM4 GPIO? As far as I can tell it doesnt register with any GPIO when pressed.
What GPIO does the fan header connect to?
Are there any other GPIO available on the board on pads that I can access?

Any help would be greatly appreciated. Or if there is a PCB layout available, I’d be happy to see it.