One rookie mistake I made was to remain unaware of the micro versions of MI modules, esp Plaits, Clouds, but I believe Yarns and Rings are also available. Michigan Synth Works has some nice ones and there are pre-assembled Antumbra modules on eBay. So your Plaits and Clouds shrink to 8 HP and you can squeeze in some other neat stuff.
Also, are you dead set on the Atlantis? Seems rather voluminous for the HP. You could add a XAOC Zadar for 8(!) ADSR envelopes or Stages and a flexible OSC.
Regarding the Polaris: check out Three Sisters and the new QPAS, as they might offer some more flavor.
Also, a dedicated sequencer on the modular seems like something you might want. Rene MKII reigns supreme, but the Mimetic Digitalis is a superb and compact 4 track 16 step sequencer at 10 HP.
Disting MK4 seems to be missing and the Poti is a neat expansion of the Batumi.
Regarding clocking... how about a Hexinverter Mutant Brain instead of Yarns? Pam’s would then be your clock divider.