I believe the traction problem is insurmountable. Aprons have fuel spillages, de-icing residues, oil spillages. Put a little covering of water on that, and traction using just 2 nosewheel tyres (no tread) is not possible, especially when there is an upslope, as taxiways often have. Parking positions are usually depressed making initial movement difficult. Even with a heavyish 737, in the rain, a large pushback tug with a big engine can have trouble to the extent that the groundcrew occasionally ask for the start to be delayed to avoid having to push against the aircraft engines. If a large aircraft tug with a big diesel e.ngine can struggle sometimes, how can a small electric motor cope? I would have thought it would require a larger APU to be certified.
Good luck if you can pull it off, but I cannot see it working.