If I had the same requirements
portable
interface with instrument
interface with pedals
interface with computer (vcvrack)
I would do this instead - minimum viable starting synth:
buy a tip top mantis (better hp/$ ratio and still portable)
get a rack mounted instrument interface (either doepfer or befaco)
get a rack mounted pedal interface (or 2) - possibly ALM SBGs, maybe doepfer or addac
get a rack mounted expression pedal interface (or 2) probably addac
get a disting mk4
get an es8 or es9
get mutable instruments links and kinks (a basic utility powerhouse, you will want something like these sooner or later)
get a quad vca (the one you have in the rack already seems ok, personally I'd go with veils)
get one of the effects modules from above - either the morphagene or the mimeophon
why get in the rack interfaces instead of the intrfx:
I just googled it - it seems ok for what it is but you'd probably want 2 or 3 anyway: 1 for bass in, and at least one or 2 for effects pedals and on top of that it didn't appear to have any more functionality than level and format swapping - don't you want envelope and pitch following and gate extraction?!? and using an expression pedal or 2 to control the modular whilst you are playing bass is also useful
after those I'd probably want to get maths, the other make noise effect and maybe a vco next
but, I'd want to go slowly and learn each module pretty well and how it interacts with other modules first and when selecting the next module to buy I'd like to think I'd consider if I have enough utilities to support my new module, and if not what I would need to add and then get it at the same time
"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