Hmmmm...OK, the first immediate issue here seems to be module size vs. case size. If you're insisting on using "big" modules like the above, you're going to have to go much bigger on the cab itself. As in, say, 2 x 168 hp big.
OR...you can go to a 2 x 104 like the Mantis or even some 126 hp widths like you see from MDLR Case and Case From Lake, but shrink the modules down to a more sensible size.
Case in point: you have a Grids in the build. Now, ignoring the simple fact that Grids is discontinued, it fits into 16 hp...if you can find one. Now, click here: https://www.modulargrid.net/e/calsynth-ugrids-matte-black-aluminum That's ALSO a grids...but a clone of the original, with the same (open source) circuitry, but it fits into HALF the space. It's also available new, whereas the original is not. Another example here would have to be the Behringer 911. OK...it's an ADSR envelope generator, no CV ins, fits in 8 hp. Then you flip around to Doepfer's listings, and there you'll find their A-140-2. 8 hp, check. But one ADSR? No, this has TWO. And you also get CV over duration! Yes, it's more expensive...but as a rule, much of Eurorack follows the ubiquitous "You get what you pay for" rule.
My suggestion would be to take this rack and then see how to replace the single function modules at the larger sizes with multifunction ones at smaller sizes. With the possible exception of the Maths, Pressure Points, and Pam's, everything else you see there has variants of some sort that up the functionality, shrink things down so that more can be added, or both. And again...larger case. Fact is, you should design this in a MUCH bigger cab first...then start shrinking things down while aiming for that Mantis form factor.