Hmmm...keep in mind that that contact mic is going to pick up every little bonk and scrape in the cab. You'd probably be better off using an actual one such as this: https://www.perfectcircuit.com/crank-sturgeon-classic-contact-mic.html and inputting it thru the A-119. The Ears is a great module...but it needs to be in a separate enclosure along with similar things, such as a small 4ms Pod or such, not where it'll pick up a lot of jostling around.
As for logic: look into adding a comparator or two. These can be a lot of fun, as they output a gate when a given voltage threshold is crossed. That way, you can use an AND gate to let an LFO switch a sequencer clock on and off by outputting the AND to a linear VCA that's passing the clock, and by inputting the AND with the comparator output and another gate signal, such as from a clock divider/counter. That's just one example.
Stereo mixer? Check Qu-bit's Mixology...gives you CV over level (VCA), pan, AUX send, plus you get a proper parallel FX send/return, and manual solo/mute switching. As of late, I think that might be the best bang-for-the-buck stereo performance mixer.