EmulatorII-list

"""When plugged in the individual outs, the sound would play only once  
every 8 key attacks. Is this normal with the E2?"""

Absolutely - unless you ASSIGN your Sounds to the equivalent channel.
(if you want to test output channel 1 -> assign the voices to channel
1, same with the other channels...) 

"""I was able to isolate the bad voice to channel 7, which instead of 
the sound, would play only a barely audible noisy "swoosh"."""

Good!, so now you got the "bad" channel.

I'm wondering, too, why channel 7 still gives bad results although you
swapped the SSM with channel 8...

What I would do FIRST next, is to clean and reseat ALL chips belonging
to CHANNEL 7 on the OUTPUT board.
Then check again.

If the problem still exists afterwards, then I would go on and do the
same with all chips on the digital board (which is HORROR and takes
you a day :(

Hope you'll get it fixed...
Greetz,
Elm.