But it’s soooo close!
Damn you iFixit for showing the tear down but not mentioning there is some sort of Rubik’s Cube-like twist in assembling the cover. I figured out the capacitive touch sensor problem (I will add photos later), but there is cover has to go back on in just the right way. It seems like it needs to hinge on from the front, while the left-hand front corner seems to be tricky… this should be the home stretch for finishing this upgrade!
By the way, I know this is probably child’s play to a mechanical or industrial engineer!