Oh yeah, I was able to just use some normal resistors and now it works!
I messed up the keyboard port (the pins are too small), so I'll have to replace them and resolder that. Fortunately, the GPIO pins that I got for the hat extended upwards, so I could just improvise.
I didn't really think of the final form factor too much, though... not sure how I'll put this in a box with a battery.
Well, something for future me to worry about.