OP do you have apple care?
A friend of mine accidentally hit like 8 cups of water onto my backpack that had my mbp in it. Well anyways when I got it out it had many of the problems you had. Sketchy battery life, just some crap wouldn't work.
Well anyways I tried everything I could do on my own, and well after they all failed I just manned up took it to the Apple store and hoped for the best. I was hoping they didn't have any water sensors inside of it, but they did. Well the guy pretty much said since it was the first time reporting accidentally damage they covered the costs, would of been around $850 or so to fix it.
So yea hopefully u have Apple Care lol.