User blog comment:The Koromo/Chapter 758 Review: Again/@comment-4493594-20140828204202/@comment-5115277-20140829074400

The SBS thing was just saying which type is their specialty. There's evidence that Sanji and Zoro can use both, and Luffy can of course use all three.

As for the other thing, Rayleigh did say in Chapter 597 that "Haki is a power that exists in all humans", and Thunder Soldier mentioned the "Power of humans" when he was training Rebecca in Chapter 733 (which seems to refer to Haki, even if it wasn't explicitly stated). Even if that was a requirement though, eating the human fruit should be enough for Chopper to be able to use it (the fact that he can speak and think like a human even in full beast form shows that the human aspects granted by the fruit are permanent). And since Haki comes from the spirit and not the body, there should be no obstacles for Franky/Brook using it.