Hmmm, guess I didn't see the expander... Without VCV rack or similar then you will want to consider some further utilities for the remaining 15 hp that you have. What are you aiming for with this rack? In any case, I recommend s/h (I really like After Later's SHTH, which is quite powerful in 2 hp), more vca's (happy nerding 3xVCA or a veils clone), and maybe something further swiss army knives like like Frap Tools 321 or SSF Toolbox if you can still find one.
Also, if you've already got the ES-9 and Ableton, might as well get VCV Rack, it's free afterall. It will open up a lot of potential utilities so you can see which ones you use the most.