We all know that this is generally a no-no, but I did a little experiment.
Two unsensored bldc motors (same model/size/kv) to one unsensored esc worked when unloaded, but there was excessive heat and differences in rpm when run under load, which makes sense.
WHAT IF we tried one sensored motor and one unsensored motor connected to a sensored esc? If I had these parts on hand, I would’ve tried this already. The unsensored motor (in a sense, the slave motor) should spin at nearly the same rpm as the sensored motor, even under load, if the load is evenly distributed.