A few thoughts.

  1. Add a link to your post rather than a jpg so we can go to your rack directly and see the modules.
  2. Rack size. You're asking to do quite a lot in one small rack. What case do you have, or are you still looking? Unless you have the rack already, your should go bigger than you think you need. You're gonna expand, no doubt about it.
  3. Drums. Unfortunately, it's probably going to be a lot more cost-effective to do drums out of the rack. However, it's by no means impossible to do them in rack (I often do), it just it typically takes a good deal of patching and hp to make them work as fully as outboard gear.
  4. Modulators and utilities. Can't be overstated how useful these are in bringing the system together. Think of them as the framing pieces that allow you to use your bigger ticket items. In my opinion, these are what make modular systems distinct from other synthesizers - gaining access to the usually hidden circuitry and allowing for unusual and sound-warping signal paths. This subject has been talked about a bunch on here, so I'd definitely search forums for deeper discussions.

Hope these help!