Need help with a special relativity question?

Something you have overlooked is that that Earth is moving in a (roughly) circular orbit, and the distance you have been given is the radius of the orbit, rather than the cirference. However, do you need to bear in mind that the Earth is rotating, so unless those people are standing at the poles, that affects their motion relative to the sun? Also, at risk of a complication too far, the sun is rotating, and this should affect any essment of how the Earth is moving in the sun's frame of reference!