pedals, buffers

[Kiwiburger]

It's not always easy or possible to convert a pedal to true-bypass. I can tell by your question that you wouldn't be able to do this. You would be best to go to Analogman or Keely, or other pedal experts who regularly modify pedals to make them quieter or true-bypass.

If it's for recording, if you don't intend to use the pedal, don't plug it into the chain.

Some of the worse offenders are cheap eq and compressor pedals. For recording, you probably don't want to use these at all - use some serious studio hardware, or even plugins will be better than most of these.

For live? Does your amp have an effects loop? Inserting them at line level means their self noise won't get as much gain as inserting them right at the front end. For live, I think digital solutions have a place. EQ and compression, and automating/saving gain structures are things that digital can do fairly quietly - use them as the front end to a tube amp. Works for the Edge.

You could make a custom pedal board with your own switches, to bypass noisy pedals when you don't want them.