Answer to: Maximum RAM Upgrade for 1286ATry using "Mactracker" (http://itunes.apple.com/us/app/mactracke...), it's a free application that'll tell you the maximum amount of ram your Mac will support, along with pretty much everything you need to know about every other Apple product ever made.
Answer to: Logic Board Reflow QuestionReflowing a chip is a solution for chips lifting off the board due to shoddy solder(ing) and won't have any effect on a water damaged board. That being said, you could try "baking" the board for a short time at a low temperature to try and evaporate any remaining water, but I wouldn't get your hopes up.
Answer to: I installed a new vibrator but its not vibratingThe contacts on the vibrator motor or the logic board are probably dirty or not completely touching. Open up your iPhone again, clean the contacts with a dry cotton swab, and try again. Cheers.