Ad 1) There is a file (in attachment) with some data.
Ad 2) Yes, I think the eccentricity might be small.
Ad 3) Data come from the picture of wild boar’s tusk, which was located in Geogebra and the coordinates of the boundary were determined. I am not sure if it is necessary before looking for the best fitting curve to rotate the coordinates.
Ad 4) I have only a portion of the arc. The arc of wild boar’s tusk is usually in a range up to 180°.
Thanks for your interest.