Does it hurt a electric motor to spin it with no power to it? I can't see how, as long as the speed was in the motor's operating range. Now changing speed of that spinning mass might take more power. Would need to compare weights, armatures of the motor to the axles+driveshaft+extra power needed because spinning driveshaft so much faster. Friction, the motor would no doubt be less.
Unless there is some kind of lube system that needs to be driven from something besides the spinning motor, I can see no mechanical issue in towing a E car 4 down. (The issue with most cars is the if the engine is not spinning, the pump doesn't lubricate the bearings in transmission)
Now if you are towing 4 down, it would be simple to use regenerative braking to get to the CG with fully charged battery. More of a issue might be the battery fully charged early in the day, now you can't get regen braking.
If you moved often enough, like every 2 weeks, and in the course of that 2 weeks did not drive the toad more than it's between charge range, would not need to charge in a CG. And for the people that use E cars, what percentage off the time do you get home with near full discharge, and need full charge in the morning? Would get to CG at say 50%, and have 75% in the morning work?