Thread: my last 28 hp
I'd add a second mixer like a Blue Lantern Stereo Sir-Mix-A-Lot. The A138 is a 4 input mono mixer.
Modules that have stereo outs:
Clouds
Erbe-Verb
Morphagene
Rings (not stereo but even and odd harmonics)
The Mix-A-Lot has 6 mono inputs (with pan) and two stereo returns. Your A-138 can be used for mono sub-mixing or mixing CV signals.
Your only source of sequencing is the tiny Erica module. Will that be enough?