form our perspective looking into 3d time I believe - if I understand correctly - I can't! All I see is what the effect of the 3d time motion bleeds into our 3d space?
Yes, because the atoms of your retina are localized in space and in time they are spread out, therefore you cannot establish a fixed reference system in time and refer to it in order to form a temporal image when photons strike the atoms of your retina.
That does not mean that you cannot construct an optical or electronic experiment that will form a stationary temporal reference system on the basis of one particle. EPR entanglement comes to mind here....
Motion means change of position in 3D space as I observe an object
In RS motion is a much more generalized concept and it does not require objects for its definition and existence.
You should really think what is needed to evaluate a position in 3D extension space, e.g.: touch & sight (parallax, intensity, triangulation).
...and whether it is even possible to do that without collisions of any kind.
Would you agree that collisions are superpositions of motions ? e.g. when a photon collides with a proton...