For the last part, after looking at a screenshot I had of my guiding screen, the Star (x,y) appears to be the star selected in the crosshairs. I'm not sure there is anything for us to do with that information. Probably more useful if you're using single star guiding and maybe you want to try finding the same star again as long as the mount hasn't moved? Not sure what else it's good for, but I'm sure somebody knows! I stick with multi-star guiding and don't fiddle with guide star selection.
