Solving Op-Amp Instability
wanted to put in a different op-amp that would sound more "colored" in the preamp stage.

I think that replacing the TL072 with a "better" opamp like the OPA2134 would actually make the sound less coloured. If there was any "colouring".

You seem to ignore the fact that this circuit is designed around the TL072. 

Assuming a circuit is well designed in an electronic sense, the added distortion should be extremely low.

The idea behind using an opamp is that the components around the opamp determine the circuit's behavior and not the opamp. If the opamp does determine the behavior, you're asking to much of that opamp and should be using a "better" one.

Now this circuit looks a bit weird to me. I do not like the many 1N4148 diodes as they're in reverse and could add noise. No idea how bad this is as it also depends on the nominal signal levels. The circuit around the two NPNs is also a bit weird with a DC feedback path through the NPN.

The bandwidth of the circuit is a combination of the TL072's own BW and the 2 feedback caps around it (33pF and 47 pF). If you only replace the TL072 with anything else you'd have to re-design the frequency compensation.

Lots of pops and noises while adjusting the pot which is VR1

That has nothing to do with any opamp. My guess is there's dust in the pot causing bad contact and thus crackling and/or a DC voltage across it while there should not be.