Water shorted out something in the system ... battery, logic board, graphics card ...
Only a Genius Bar tech *would* have known, but you complicated things with your DIY disassembly.
Ask Genius Bar if you want, but possibly/probably the only thing you can salvage now is data off the hard drive to use on your new system.
Used to repair laptops for years,.....you said "there was a little puff of smoke"
Answer, the logic board at the very LEAST is fried,..you blew some micro resistors and likely smoked the untold havoc on the logic.
Looking inside isnt going to solve anything, you CANNOT fix anything,......replace parts yes.....fix NO WAY.
Days of "fixing things" inside laptops died almost 18 years ago. Things are too small, and its too much fuss.
everything now is:
A: find broken
B: toss broken
C: install new.