Can a BLDC generator power another identical brushless motor?
Yes. One BLDC motor can be used as a generator to drive another. 

However, this is only really useful for a quick test or demonstration of a motor. The generating motor only produces voltage while it's being turned. If the generator is turned too slowly, it may not generate enough voltage to overcome the friction or load of the motor. If the motors are of different sizes, use the larger one for the generator.

If you connect the three wires of the motor at random to the generator, then the motor will turn one way or the other. You can switch the direction by swapping any two phases, it doesn't matter which.