FYI, my votes for both the extra filter and the waveshaper both go to Tiptop. Their Steiner clone (Forbidden Planet) is perhaps a tad more spot-on than Arturia's (and I own a MicroBrute plus did own a Synthacon for some time), and that wavefolder + divider module is pure usefulness. Plus, a third vote for yet another Tiptop device, the MISO...one of the better CV/mod router/modifiers in a while, at a stoopid-cheap price to boot. And yes, you're going to need that MISO, because generative involves a lot of tinkering with control signals, and that module makes it easy to work them "live", like a configurable controller.
Oh, and as modulation sources go, have a look-see about jamming a Maths in there. Yeah, everyone gets those...but it's because they work as advertised, plus pairing something that can do complex slopes with the Marbles...oh, yeah, classic generative stuff there.