Other 2 ruins located somewhere on a line aproximately 1300km from the ruins, yes.
The line was derived with help of putting in tetrahedron with two of its points being ruins and planet centre. It is actually 3D sphere, just made a screenshot from the side to make circle line proportions to be more clear. Note that sphere has radius of 1487 instead of 12xx-something our planet has, due to my attempts to combine it with planet mapper which uses merope 5 planet, but all proportions are correct. Technically I think I can derive planet coordinates and bearing for the line, but I have been pondering over this puzzle for almost entire day and too tired, so sry, maybe tomorrow, unless someone hopefully beats me to it.
Not a bad thought, but remember, we got more data points than was planned from this site. Which means each site probably gives around 13 data messages. So 6 or 7 sites total. Maybe even more. Infact, these sites could be like barnacles. There may be dozens.