Chosen Solution
What would happen if you attach the IPD flex ribbon Keyboard flex ribbon cable going the wrong way from the keyboard to trackpad or trackpad to keyboard, and then power it on (basically installed upside down). Would that destroy the keyboard? There are 2 different cables, but the one im worried about is this one:
and the way the image is shown is the correct way to install it, but what happens if you install it this way:
UPDATE: I replaced the trackpad with a working one from iFixit, and the trackpad and keyboard are working fine now. Thanks, see below for the accepted answer.
There’s a very large possibility you damaged the logic board and/or the trackpad! The cable is not a one for one connection, it’s polarized.
