This is almost certainly your issue. Good on you for digging this deep into the repair.
That pin, according to the documents I have, goes from that connector to the CPU and nowhere else (aside from a test point on the back of the board). These sort of connectors can definitely be replaced, the pin itself may be able to be replaced, or at least rigged so it can be used without replacing the whole connector, but it depends on what the damage is specifically.
iFixit even sells [product|IF277-007|this replacement connector|new_window=true]. But it will require microsoldering skills to replace. If you do not possess those skills yourself, see if there are any local shops that do board level repair.