I appreciate your "I'm married to the case statement" - but seriously get a divorce and get a mantis - much better value. in the long term and easily portable unless you are a small child and the 'included' modules don't really save any money and tie you into buying 1u modules to use them
BUT
how are you planning on sequencing v/oct for rings/uBurst? I think you may need the 1u midi module - the case provides only the usb or din via trrs inputs - NOT the cv/gate that you need to sequence a modular
you probably want to get the 1u line out module - so you can use the case outputs
I don't see the need for steppy at all - it seems completely irrelevant - there is nothing here that begs to be trigger sequenced
I would dump 2 of - pams, batumi and sloths - probably keep batumi and add a 1u sloth - maybe swap batumi for zadar? - you simply have too much modulation in too small a rack with not enough to actually modulate!!!
I would get rid of both of the vcas and the stereo line in - and replace with a good quad cascading vca - veils or intellijel - they are pretty much the only ones that amplify and will function perfectly as line ins (appropriate cable required)
I would add kinks - incredibly useful set of tools in a small space
this may leave you enough space to add a stereo mixer and maybe a second filter
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities