#1
Its possible to make a pedal withouta switch right? i can just use stereo jacks to turn it on/off with the guitar jack right?

Oh yeah and one more random queistion, in theory, you could make a circuit out of nothing but potentiometeres right? They are variable resistors, so would that work? Im not going to do this but wouldnt it be easier to bias amps if it was like taht?
#2
yea you can use a stereo jack for the input so when you unplug the power goes off. This doesnt work as a bypass though, it wound let sound go through.

You can use pots or trimpots as resistors as far as I know. You just have to know where to put the 3rd lead which is connected the the 1st lead (as far as I know).
#3
amps ARE biased using potentiometers (they usually use miniature pots called trim pots). well, unless they're set-biased

all you need to do is hook up one pole of the pot to one end, and the other two to the other end (or just the middle one, either way it doesn't matter)