Your issue is being 100% certain you do not adversely affect the rise and run. Every step needs to be dam near the same, with a minimum and maximun rise and run, as well as tread depth. Be certain this guy knows what he is doing or you may not get a cert of occupany when he is done.

I like a white riser against wood, personally. If this is a long term home, ask yourself which do you like more, wrought iron or painted white, go with your preference.

I like white risers, too. Lightens up a stairwell and I feel the contrast between riser and tread makes the stairs a bit safer by visually separating tread from riser.

Thanks. I will check with the township in building codes for the steps.
Also is it better to install new hardwood floor with bullnose or just stain the existing step(it’s about 40 yrs old) to match.

Shoes are not allowed in my house. I love white painted risers and if there are no shoes involved, then it isn't a problem. I don't like carpet on stairs because I would rather poke my eyes out than vacuum carpeted stairs. As for iron or wood spindles, it's just another fad thing. In the 60's and early 70's everyone wanted wrought iron. Then it wasn't "in" so everyone went the wood and turned spindle route. Then it's back to wrought iron once again. And don't forget the polished brass nightmare that made everyone go to nickel, then oil rubbed finish, then to black and now brushed brass. I always just stick to polished chrome as that never goes out of style and is timeless. Painted risers have withstood the test of time. I also like painted spindles. Do what you like and try not to be too influenced by flighty trends.

And one more thing...whatever color your floor is should be the color of the handrail

We are installing hardwood on the steps and riser. Planning on staying in hand rail same as floor. I saw these balusters at Lowe’s and I like them. Not sure about how it will look or quality of the baluster? Anyone ever use this company? The pictures show the color of the flooring.

https://www.lowes.com/pd/Creative-Stair-Parts-44-in-Matte-Nickel-Wrought-Iron-Classic-Stair-Baluster/1000510443

A good floor person can stain the existing treads to match if they are in decent condition (and the same species). I don't think a good floor person would suggest putting flooring on the risers--they are usually a single chunk of wood. (If your flooring is wide enough, it would probably be okay though. They just aren't supposed to look like floorboards.)

Are you planning on replacing the treads with new treads or just going over them with flooring? (Don't do that!)

And finally, I think that spindle is just about dated already and no better than what you've got. Your existing is pretty classic and if you want to change it, painting would look really nice. Stain the rail to match the floor and paint the rest! (Especially keep it all if you reuse the existing treads. Gotta pay attention to the holes!)

Janice was on the money! Listen to the folks above. Good luck.