I’ll make an observation here and then I’ll wait for Barry to elaborate on what he found when he did an extensive evaluation of his pedal board.
The traditional thinking on a fuzz pedal is to place it first in line after the guitar since the pickups are a higher impedance than a buffer output. In other words, it sounds better.
After the fuzz, you can then add other pedals to perform tasks such as adding distortion, compression, delay, tremolo, phase shifting, etc. Typically, you want to maintain a unity level as the signal passes through each pedal until you reach the end of the chain. This is where most folks that wish to overdrive the front end of their amp would add an additional boost or overdrive to raise the final signal level. This final boost or the last pedal in the chain also provides a low impedance signal which can drive long cable runs and matches nicely with the front end of the amplifier. This is also a perfect place to add a Solo switch feature to provide two volume levels for featuring the guitarist in the mix. You don’t need two buffers to do this.)
If you follow the above sequence of pedals, you will not alter the tone of the fuzz when it is activated except for changes made downstream. When it is bypassed, the next pedal in the chain will take the guitar signal and modify it with its effect before sending it out through its low impedance output. (Most pedals are designed with a high impedance input stage and a low impedance output stage which is what a buffer has.)
I yield the floor to Barry and others.