Basically it would act as a pedalboard on/off switch for gigs.

The goal here is to have a bog standard effects loop, flanked by two buffers (in and out) which are always on. The tweak would be to make each of these buffers (say, each side of a TL072 or most dual opamps) 1) as transparent as possible and 2) with a variable boost.
Now I'm no electronics engineer, so I took existing buffer/boost designs, got the schematics online and as the pedal was designed by a very good friend of mine, great guy, and great electronician I won't state which it is and I'd appreciate if no one asked. This is just however a clean boost/buffer, no rocket science as far as I know.

Here's the input buffer:

And the output buffer/boost:

Now there's a filter at the very start of the input buffer... do I need this? I don't exactly get what it does. In said pedal those buffers are incredible. Really brings out a certain sparkle in my sound, but without changing it that much at all, in fact I couldn't tell the difference.

The output buffer also starts with a filter, but that used to come after a whole (switchable) drive circuit so I'm wondering if I could make do without it?
Also, can I just 'copy' the boost section of the output buffer and place it onto the input buffer and get the same results?
Finally, would sticking those two diagrams together make electronical sense and give me the results I need? Could I replace the opamp with a single TL072 or would that require a change of values? This pedal uses the LF347 but it's interchangeable with the TL074.

As I get it, R2 (input) and R11 (output) are the main elements of in/output impedance right?
Anyway... it'd be a three footswitches box with two knobs (the boosts levels). DPDTs for switching between boosts/neutral buffers, a 3PDT with LED for the middle effect loop and a DPDT for the output boost/buffer. This way I'd get a clean boost to stack with other pedals when the center loop is on, or simply two levels of additional gain/loudness when straight to the amplifier, the whole lot being buffered to make do for long cables.