Thanks for the list!
As to real and unreal

I personally didn't give any thought to who was real or fictional, I just popped out a long list of 'famous' duos, then cut that down to 25 faves. Looking it over, even without factoring that in, I wound up with a list that was pretty well balanced between the two.
And yeah, I was trying to nudge us towards 'famous' duos, in an attempt to narrow the choices down, even if by a shade. I gave the Wayne/Hardy example, another would be McCartney, who has paired up with folks like Wonder, Jackson, and Costello over the course of his career, but when you think of him, he's most well known for his songwriting work with that fellow named Lennon.