Generally the autopilot functions are split into two groups, engage the autopilot stability before take off and then engage the 'upper modes' eg heading, alt, IAS etc once through 60 kts and 400 feet.
As you suggest, smaller, wheeled helis use tail rotor thrust to change direction via the yaw pedals during taxi so heading hold would not be engaged at that time and in most helis is not available until around plus of 60 kts.
Perhaps someone operating pre-programmed uavs could give a better example?