Macbook Pro 8,1 turns on during SMC reset, does not reset

Hi, I'm troubleshooting a friend's Macbook Pro 8,1 - which has faced a number of low-level problems since she dumped juice on the keyboard a few months ago. The biggest problems appear to be SMC related (summarized below).

When trying to do an SMC reset (http://support.apple.com/kb/ht3964) by holding Shift + Option + Control + Power, and releasing all buttong simultaneously, the computer simply powers on. If I hold all buttons for ~5 seconds, the power LED flashes, then the computer powers on before the buttons are released. From other articles, this process should complete with the computer staying off for the duration - only turning on with a separate power button press afterwards, which makes me think the SMC has not been reset. Any thoughts on how to properly reset the SMC?

Background and list of problems persisting despite attempted SMC resets:

1. The battery stopped charging ~3 weeks ago. It ran fine until the battery died, then wouldn't turn on. We tried multiple chargers, to no avail. Miraculously, it turned on after being plugged in a few days ago, and has been operating mostly normally since.

2. Since it came back up, the computer does not sleep automatically when closing the lid, though it does manually sleep.

3. The battery power LEDs no longer light up when the side button is pressed.