I can't speak to the o2 exposure, but I do have my first sour going in one at the moment. I have four of them, 2 30's and 2 60's, I have never had a spigot leak.
Sure you can use an extension cord. I brew on the other side of my garage than my breaker is. I have a 37 foot 6/4 cable that I run across the garage on brew day
I have 7 taps, I usually only have 3 or 4 different beers. I store the rest under the stairs, which is 68-71 degrees or in the ferm chamber if it's empty.
I went ahead and did two different beers. A 60/35/5 pilsner, wheat, and oat. 1.045 with 5 ibu for the berliner. And a Tart of Darkness grain bill for the sour cherry funk.
Thanks for all the suggestions.
What percentage are you running in manual? I run 75 % in my 16 gallon kettle and 82 % in my 25 gallon kettle. My boil off is around 1.25 gallons for both.