Mike, as an engineer you're thinking of oscillators in the classic sense, e.g. sine/square/triangle/sawtooth regenerative feedback circuits. Soft synths don't actually have oscillators, as I'm sure you know. The term has merely been carried over from the hardware world out of convenience.
Some software synths are able to generate waveforms of far greater complexity than anything Bob Moog ever envisioned. For example, much of Zebra's strength is in the "oscillators", which can morph smoothly between any set of source waveforms. Melda takes a similar approach to LFOs used as modulators in various products, so I'm guessing the new synth's oscillators are based on similar principles.
Creating such waveforms isn't a simple process. You're generating very complex harmonic series that have to be band-constrained to avoid aliasing and intermodulation distortion. That can't be accomplished with a simple filter. It requires constraining harmonics at the generation phase itself. It's black-belt coding, for sure.
Bear in mind that I have no inside information about this. I'm only thinking how I would approach it.