Your post implies that you only use mu-tron and octave, then Pre and comp.
So, do you actually want Pre, mu-tron and octave, then Pre and comp?
In that case...
Bass - Pre - LS-2
Loop A: Mu-Tron - Octave
Loop B: Comp
Amp
The signal will always go through the Pre, then either mu-tron and octave OR compressor.
Shep