MacBook fix - not sucessful but not due to iFixIt parts.
Trackpad and keyboard continuously seen as being disconnected and reconnected by USB daemon. Internet was unanimous that issue was USB upper case cable.
Replaced the part (and replaced a few stripped screws too)... but issue persists. The problem : faulty upper ase cover.
When your mac starts going haywire this bad, don't invest 250$ to fix it. Buy a new computer.