About the coordinates:
You can view the coordinates of objects (see my first attached image). You can change these, even though changing the coordinates of galaxies will only move the body at the center, which has the mass, but let the particles (stars) stay in place.
About the orbits, when something orbits something else orbiting a third thing, the orbit won't appear to be round because the object it orbits is moving itself. It will look like a line zigzagging forth and back around the object orbiting the third object (second attached image).
You can verify the orbits by setting the second object (which orbits something else and also has something else orbiting itself) the object which the trails are centered on, in my example (picture 3) the Moon, which I've centered, so it's clear that Pallas orbits the Moon, which orbits the Earth.