You could match the color of your lights. There are many great metallic paints from which to choose.

I agree with either matching the satin-nickel or black.

I found great ideas looking for "library stairs" in Houzz that you may also find helpful. In my case I am trying to soften the historic incongruity of an iron spiral stair. You may just get some unexpected inspiration for what to do with yours.

I agree with black.

Be careful of the kind of black, though. Shiny or matte. Without knowing the look you're trying to achieve it's impossible to make a recommendation, but I would consider some charcoal matte colors for a truer wrought iron look.