Maths/quadrax/pams is probably more than enough for modulation - what's your use case for o&c?
O&C is a great universal module. It can do duty as a sequencer, modulation source, quantizer, and so forth. It was a module I started with and would still recommend.
mimetic digitalis looks very fiddly for a sequencer - I would do some research - if possible try one out before buying - sequencers are quite important in terms of workflow - if you don't get on with your sequencer(s) you will not get one with your modular
I own a Mimetic Digitalis. It's nice for improv stuff. I find it preferable for modulations but for note pitch... not as much. But it's 16 steps by 4 channels in a small space. If you have the room for a dedicated 16x4... by all means. But for jamming, it's nice, especially hooking it up to a couple of Euclideans for advancing steps or jumping/resetting the sequencee.
also the lack of something to combine triggers would seem frustrating - euclidean circles and pams - maybe a trigger combiner - or a switched multiple
A logic module capable of "OR" is great for combining triggers. A Blue Lantern CMOS party is $80US.
-- JimHowell1970