This sounds amazing. What I like is that both the Octo and Uni voice seem to follow the volume of your bass's signal, making them more responsive. The OC2 approach gives you that for the lower octave, but sounds like the Subt has an envelope follower for the Uni voice too.
I love using my Oxide as a synth voice, but because it's a gated fuzz, the volume is constant, which can be cool or can be limiting depending on the context.
Edit: listening again, the Octo voice isn't modulating the bass's signal, like an OC2 - it's just the waveform, so that is going through an envelope follower too.
I'm really curious as to how Taylor does the different waveforms - maybe it's a waveshaper working on the squarewave output of the OC2-style flip flops, with an octave doubler driving the Uni voice flip flop. But then the waveshape would vary from low pitches to high pitches... dunno.