You can find micro versions of Plaits and Tides. That will save you some HP to add in other modules. I would get the Poti expander for the Batumi. Being able to access the additional LFO waveforms as well as sync and reset functions without pulling the module and moving jumpers is a MUST in my opinion.
I would also look at the 2HP line and think about logic modules and switches after you get the core of your system up and running and start thinking about more complex patching.
So what's going in case #2? They don't call it Eurocrack for no reason. :)