Hello Wai! Let's see if we can help answer some questions:
- Blue loop box: Probably looking to add a true bypass (no tone suck or coloration) to some buffered-bypass pedals, OR, she just wants to be able to turn on the upper few pedals all at once and uses the loop box to do so.
- Tone Processor: Not sure what specifically in this instance you are referring to, but it may be a digital effects processor (not shown in the pedal shot?) if it's not the name of a specific pedal in and of itself.
- SansAmp into tube amp: Could be just used for the DI box aspects (run the DI to the house PA from there instead of from her amp stack), or it could be being used to add some gritty overdrive without having to actually goose the amp, or it could be used just to have a second main bass tone onhand, since the SA has a nice distinct tone that lots of people enjoy.
Hope this helps!