The instantaneous velocity of a point in 3D space can be found from the linear distance it moves between frames, as you wrote: distance=sqrt(x^2+y^2+z^2). If the point is moving along some arc, it could instead be expressed as an equivalent angular velocity about some point, but you would not add an angular velocity component to the linear component: they would be two alternate ways of expressing the same instantaneous velocity.
If you did express the motion as an angular velocity about a point, this could then be converted back to an instantaneous linear velocity.