Then I would take two oscillators, run them through something to combine the waveforms, and then have that CV signal going into the VCA.
The output of that something is probably an audio signal, no CV?
Where would I send the CV out from the sequencer to? To which oscillators 1v/oct input if there are two going into the VCA?
You can always mult the CV.
While I am not quite sure what you try to achieve you can always test those basic building blocks in the TrueGrid synth here on MG. I have setup a small system according how I think you might want to patch stuff.
https://www.modulargrid.net/e/racks/synth/180172/1121