Hello,
Yes the ability to display the coordinates for a specifc cross marker would be nice. I'll add it to the suggestion list or maybe implement it if I can do so quickly.
Regarding export to spreadsheet, I'm not sure what would be the best way to display these data…
Currently we just group objects by type and list their various values over time. When there are several object of the same type on the same image, we can't differenciate them. (for Tracks and Stopwatches, there is a title to help, but for lines, angles and soon single points, there is nothing).
If you have many points on the same image, I don't know you will be able to set them appart for further calculations…