Respuesta a "Trackpad partly stopped functioning after tea spill?"I had exactly the same problem, after I accidentally droped a chai tea over the keyboard , luckily I had one of those silicone cover so it did not get too much through the keyboard. I followed the same steps as you describe in your question, in a short term everything seemed to work right, after a while the trackpad click started to fail, the day after I could not click at all. My solution was to replace the trackpad, its a very easy procedure and fortunatelly I had a broken 13 MBP I could take the part from. Now it works as expected.
Respuesta a "My MBP won't boot, with horizontal line at apple logo"After receiving the new battery the issue persists. Then i found this link https://www.apple.com/support/macbookpro-videoissues/, apparently there is a known video issue for 15-inch and 17-inch MacBook Pro models manufactured in 2011 and 15-inch MacBook Pro with Retina models manufactured from Mid 2012 to Early 2013. You can check in the link if your macbook is under the repair extension program and they would fix it for free. Mine does. Update: The program has ended now