Although Marlin believes there is only one stepper, you are able to send T0 / T1 toolchanges and the right stepper extrudes? At the right offset ?
If I got you right, you have a dual extruder setup, not switching extruder. You can make the slicer do the toolchange things, like servo angle and offset control.
If I got you right, you have a dual extruder setup, not switching extruder. You can make the slicer do the toolchange things, like servo angle and offset control.