1) Sorry guys, but there is no koshi nage in judo....
2)The main difference I can see (which is a big difference by the way) is that aikido's koshi nage is executed at a 90 degree angle betweem nage and uke feet, while in judo, uke and tori feet and hips are usually parallel or almost parallel....
3)In judo, you can throw an unwilling person using a hip throw (even if he's pulling backwards, while in aikido nage should be using uke's movement otherwise it would be more difficult to execute.
1) See the link at "Jigoro Kano--Founder of Judo: Uki goshi" at http://188.8.131.52/judoinfo/video/video4.htm
. It sure looks to me as if Mr. Kano is doing a textbook KOSHI.
2) Granted. But, er, see no. 1, above.
3) Kano used to criticize his people for doing judo like oxen. I'd guess he had in mind what you allow as passing for judo. You can force technique in aikido, too.