As a beginner, it is extremely unlikely that you would be able to learn how to hover a helicopter without a gyro.
Yes. Many people have mentioned that they were unable to hover their helicopter until they installed a heading hold gyro.
The short answer is: no. Gyros (as used in model helicopters) are only sensitive to angular acceleration and not linear acceleration. Therefore, they would only help stabilize the tilt of the helicopter and not the movement of the helicopter, regardless of whether yaw rate or heading hold gyros are used.