A few things jump out...
First, are you planning on racking the subharmonicon and you actually have two rows available, or is that just for representation? If the former, I'd recommend keeping the subharmonicon in it's case and keeping the hp available. Also, will you be connecting this to the other rack, or is it completely standalone?
60 hp is really small for modular. While you absolutely can build a rack in that space (depending on your goals, I'd think), it's not so simple. You have to be quite selective about what makes it in if you're going to get something that works as intended. If a bigger rack is possible, you won't regret it
I'm not seeing a lot of modulators. Yeah, there's Pams, which gives plenty of interesting gates, envelopes, and attenuation, but how else will you be generating cv signals or moving parameters? You need to consider LFOs. Something like the Xaoc Batumi gives you a bunch in a decent footprint, and Divkid's Ochd (now with expander!) is quickly becoming essential in my rack.
Also, you don't have the utilities that will be necessary to get the most out of your modulators. Attenuators, VCAs, slew limiters, s/h, you'll get a lot of modulating mileage about these types of modules. If you're looking to explore sounds, don't discount randomness. Thank you Pams for offering this, but look at something like Instruo's tagh is an interesting option to add more random flavor.
Good luck!