The closet I’ve seen to variable background colors in Axure is the workaround described in this thread. However, the color is only available at run time not design time, making it a bit difficult to use in a library.
I don’t really have any good suggestions for this unfortunately, when it comes to page-level data, I’ve tried creating blank template where the page-level values are already set but that gets quite difficult to maintain over time.
I’m hoping someone comes up with something for this, it would save me a lot of work too.