Don't think I could whittle it down to three. As well as those already mentioned there's people like Ollie Mcloughlin, Jimmy Wisner, Robert Banks, HB Barnum, all that Chicago stuff from Carl Davis and Willie Henderson...
And then there are the Arrangers too. Think about the contribution to this thing we call Northern Soul by guys like Arthur Wright and the kickass sound of Miles Grayson. That's just a few from the top of my head. good thread though
Godz