Hello!!  Has anyone added fondant to cake separator pillars?? This may sound odd but I'd like to create a different look to the plain white pillars and I'm wondering if anyone has done this before.  

I have not, but I see no reason why you shouldn't do it.

I don't exactly remember using fondant but I have decorated tons of pillars with tons of things -- fondant is fine to use as well

As k8 said pillars certainly can be decorated 

As k8 said pillars certainly can be decorated