MacBook keyboard repair after spill?

MacBook 13" Unibody Late 2009

A couple days ago, I spilled water into my 2009 MacBook keyboard and after letting dry for 48 hours found that the keyboard does not work. So I have two questions:

1. Someone suggested replacing the whole upper case, but is there a way to replace just the keyboard itself as I understand the upper case replacement process is rather difficult?

2. Over the past 24 hours or so, a couple keys have slowly either had partial or full functionality return to them. I am thinking that maybe there is still some water residue stuck in the plastic layers of the keyboard? Is it possible that eventually full functionality will return? I do not want to waste $150+ fixing something that might fix itself :) The liquid was only about 50ml or so of bottled water.

Also I noticed that strangely sometimes the computer restarts when I press sleep or close the lid, could this be related to the keyboard and possibly fixed by a repaired one or does this likely have to do with the logic board?(Sleep LED also not strobing) Or are there any tests I could run on the computer to check for damage? There was hardly any water on the main board when I opened it right after the spill. I would appreciate any advice on what is the cheapest and easiest way to fix this!