For a FX rack better leave the voices out. As I understood you want to process your other synths.
I would keep the Ikarie and drop the rest for other stuff.
For Fx Rack:
-I like hands on modules like: Mimeophon as Delay, Reverb and Stereo-Feedback looper, all in one.
-Qu-bit Data Bender is nice for processing.
-Small and slow modulation sources like Divkid Ochd + Expander or NC Triple Sloths are useful
-Bastl Neo Trinity could be a good Modulation Hub for a rack of this size.
-Ikarie is cool for stereo filter, with drive
-There very small versions of rings and clouds, like nanorings and uClouds.
Greetings
Chris