VCAs, for starters. Right now, you have no way other than manual control to impose an "envelope" on your sounds. That's the sort of thing that's pretty much a "fatal error" in most builds.
Your biggest problem here is, in fact, the Cre8 cab itself. I know you see loads of single-row "beauty case" builds on YouTube, but it's worth noting that those usually fall into two camps:
1) The build is a very specialized device that's not suitable as an all-around modular system. Or...
2) The build HAS everything, including absolutely no space for your fingers whatsoever.
Neither of these are of much use, really. What I would suggest is to strongly consider a larger cab to accommodate a much larger (and far more comprehensive) module complement so that you DO have a proper system. As for the Cre8 case...keep it, as I think you'll find that it can work nicely as a cab for your controller setup. It already has its Cells module, after all, and having the oscillator there, then adding a better controller would make that a little bit like the old ARP 2600's 3620 keyboard with its auxiliary modules and extra expression controls.