a single case will be much more useful than splitting them up and probably work out cheaper in the long run
buy one that has space free after all the modules you want now - allow 10mA per rail for power for these and allow 25-30% headroom (to allow for inrush)
it will also allow you to replace the 2hp vcas with a quad cascading one, such as veils - which are incredibly useful and give you 4 channels + mixing for about the same amount of cash - plus better ergonomics - same with the micro clone - full size modules are much nicer!!!
"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