1. Rice does nothing. Literally nothing!
2. Your going to have some corrosion issues down the line on the board. It's inevitable, unless you clean things up.
3. Your keyboard issue is probably just that, a bad keyboard... Not impossible to replace the keyboard on this model. Yes, it's a pain but not impossible. The keyboard is held in by 50 or so screws and/or rivets that you will need to cut out and replace with screws -- Thank Apple Engineers for that wonderful idea --
4. You will need to pull out the board and the I/O board to get to the keyboard so a good ultrasonic cleaning of the board would definitely be something to look into -- if that fails, a soft toothbrush and some 91% isopropyl alcohol should work fine.
5. Prolonging cleaning of the motherboard is just going to cause more problems. I'd pull the bottom cover off and unplug the battery and get that board cleaned ASAP. You got lucky.. It still turns on. Most Retina's we see here aren't so lucky and have board issues after a spill.