noob here myself with zero hands on experience but also currently planning my first rig, some thoughts:
what you can do with that pro output could very well be handled by the pc you connect that es-8 to, also some of the yarns features can be done with the es-8.
maybe add some sequencial switch like the A-151 for more evolving patches in the freed space? just an idea ;)
modules i found worth researching in general:
- batumi (also look at expert firmware features) because who does not like lfo's?
- disting mk4 (nice multipurpose for a small system)
- pitch quantizers like the ADDAC207 to get usable musical pitch-cv out of any modulation source (out of that maths for instance, or utilizing lfos as arps is also nice ;D)
- maybe some little gate-logic like the Pico Logic from ES for even more complex gates, looks like it could be best friends with to your tempi.
something deeply personal/individual:
- i just fell in love with the sound of the SSF Ultrafold and if i am not wrong i dont see any wavefolding capabilities in your rig? maybe listen to sound demos if you like dirrrrrty you may also fall in love haha ;o)
edit:
just some thought that i want to add: things like the disting mk4 and the batumi expert firmware are maybe a little less useful in real life than in theory if you are no super genious in remembering weird settings that are not written on the frontplate. they kinda go against the one-knob one-feature that modules usually tend to go.