These from the muffs order or the Kobicon non-switch stereo ones (they are identical save the switch
They look pretty much like normal “nut” style sockets, just with a different form of nut (a ring type nut, instead of a normal nut).
Sorry, are you after the eagle number for doing a PCB with them?
the foot print is different. I just burned my evening and did it myself. Learned how to import DXFs into eagle so time well spent
A calliper and a keen eye are better sometimes. I know this from spoke length calculations for bicycle wheels. Rather than trust someone else’s measurements for a hub it’s often easier to measure yourself.
i always go off the spec sheet
Yep, so long as you can find it 
Otherwise you can press it into plasticine and measure the imprint