Lot's of really good advice here. I've been going at the generative stuff for 3+ years now and other than the general rule of creating modulation and ways to trigger events from it (comparators) IMO the real key lies in the ability to 'tune' the randomness - i.e. lots and lots of attenuation + offset.
Looking at your rack so far, I'd say it really needs random sources and ways to tune it.
For modules, a few more recommendations:
Caudal from Vult. Soon to be released in physical form (it's a module in VCV rack currently). It will provide two rows four smooth randon voltage outputs. Each row can be clocked to give stepped random output (S/H) and all in 1oHP.
S/H: RND STEP from SSF/Divkid. 3 cascading S/Hs but gives uni and bi-polar outputs - uni so you can use it better for sound sculpting.
Zadar from Xaoc. Says it's an envelope generator but it's not - it's an LFO machine that's particularly good for generative in that you can loop them and CV one paramter for each of the 4 LFOs (2 if you get the 3HP expander and totally worth it).
AxB+C from Befaco. My favorite module for attentuation and offset. Also a ring mod. The dials just make it really easy for me - especially for dialing in LFOs or smooth random that then go on to feed into a function generator for Krell patches. I have a Caudal protype with a Befaco on either side for this very purpose :)