Its usually coaches/camps that come up the with gameplan, the fighters just execute them.
As for fight IQ, I think an important aspect is how a fighter adapts in there when faced with a complex puzzle they havent seen before and usually doing the right thing at the appropriate times. Id also include talent with fight IQ, I dont know if many would agree, but creativity etc, and "flowing" whilst in the zone allows you to do what I mentioned before.
I've never seen a fighter more adept at the latter than with Jon Jones, but he did tend to try beat fighters at their own game, I dont know if I'd say that wise but its worked out for him.
Id definitely say that GSP, DC, MM, Jones and Cruz are have some of the best fight IQ in the game.