Buffered power supplies for multiple circuits?

[mg.audio]

Just for fun, I'm planning a pedal that will have a bypass stomp-switch and just one rotary switch to select between six different buffers (two NPN buffers, two FET buffers, and two Op-Amp buffers). The idea is to pass it around my guit-fiddling friends and see if they can tell the difference between different buffers. There are a couple questions that popped up while thinking about the build. One is whether I should give each circuit it's own buffered power supply. Since we're talking about audio circuits that are supposed to be super-transparent, is there a good reason to do this? Are these circuits going to interfere with each other in any way?
For example, this link goes to the schematic for the Boss DS-2 -> http://www.freeinfosociety.com/electronics/schemview.php?id=132  What I have in my head is simply multiplying the buffer consisting of Q7, R15, C14, and C16, to get a 9v supply for each circuit. I'm assuming I would just have to change the value of R15 to keep the voltage at 9v instead of 8. The follow-up question I guess, if I'm wrong here, is when DO you need buffered power supplies?

The second thing is pretty simple and probably exposes my ignorance... when using a 2P6T rotary switch to select between 6 different FX loops, with the poles being the master in/out, is there a better way to avoid popping than putting a bunch of, say, 10M resistors between the pole and throw 1, pole to throw 2, pole to throw 3, etc...?

[PRR]

> keep the voltage at 9v instead of 8

There is an unavoidable 0.6V drop.

In general you can't isolate without losing some.

Yes, I do think that power filter will work for you.

[bool]

Suggestion:
halve the R15 (i.e. ~2k2)
quadruple the C14 (i.e. ~47uF)
use a high-gain high-current transistor (or a ...3904)