Vector3D _pos, _lookVector, _upVector,
_localVelocity, _axisVelocity;
Quaternion _qHeading, _qPitch;
float _pitch, _heading, _roll,
_acceleration, _friction;
bool _xLocked, _yLocked, _zLocked,
_xViewLocked, _yViewLocked, _zViewLocked,
_moving;
That looks like way too much state. In order to describe where an object is, all you need is a position (a 3D vector) and an attitude (a quaternion). I can see an argument for having an angular velocity as well (another 3D vector) if you want to use Physics on your objects. Everything else is redundant, unclear or both, and should go.