Question

Conceptual question about relativity: Imagine two events--

Answer 1

They are not the same event in that they occur in different places and times in most frames of reference. In the photon's frame they are not separated in either space nor time because photons don't experience time and at least mathematically all points on the spacetime manifold are the same point to a photon.  What the zero spacetime interval can tell us though, is that the events are connected by a light beam (light-like separation). There is as much time between the events as there is space and one event can conceptually cause the other. They are on the cusp between time-like and space-like  events.