What's driving pitch in your sequences? Steppy handles triggers but not pitch. Noise Engineering offers a 4 channel 16 step CV sequencer by the name of Mimetic Digitalis that plays nicely with Steppy, but you're out of room.

Also, consider adding a small DC-coupled mixer like a 2HP Mix (check to see if the depth is okay for your rack). Mixing CV signals together is important, like combining LFOs and ENVELOPES...