is this a second rack? (as you have called it an expansion rack)
what is in the first? or whatever you are expanding?
if it is an expansion then depending on the modules in the 1st case, it may work, but if not there are some issues
the es6 is an expander and needs es3 or es8 to work iirc
odessa is polyphonic (when the expander is added) and could probably benefit from a chord sequencer (harmonaig or sinfonion)
i'd want more mixing (but you may have this elsewhere) and not just for audio
where are your offsets and attenuators for example?
whilst random is good - it's better as a small part of something else (ie mixed and attenuated) and it may be a good idea to look at chaos as well as random (nonlinearcirucits do a lot of this)
"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