Be sure to sell or give away that beautiful old railing and not throw it on a heap. I happen to like it. But indeed, it might look better in black. The railing you have posted instead gave me some shudders. Quite a contrary style and not one I'd welcome in my home. Way too modern for a ranch home, is what comes to my mind. If you are really going to get a new railing, I like the one Judy proposed, although I wouldn't want it in white at your place. Perhaps in black and the railing that matches the wood of the stairs? Or maybe something like this?

So, the county plans to pave the space? Do they have a timeframe? I'd talk to the County Planner and ask for his suggestions. You can put forward the position that creating public parking will create more hazard for your property then leaving it garden. And this means you'll going to incure greater expense for the railing. See if they can help or add the railing to their portion of the property.

I think no cap is unique and give a sleek modern touch! Cap is more classic look so can’t go wrong if you do add. 2 good options honestly but I vote no cap

The simplest way to deal with that is to drill a horizontal hole through the top end of the railing and install a screw that is long enough to go through the wood railing, through the sheetrock, and into the wood framing in the wall at least 1". You should use a trim head screw -- a special screw with a small head -- and install it with an impact driver. When you're done, the head of the screw should be just beneath the wood surface of the railing so you can patch the small hole with wood filler. If you don't have the experience, skills, and tools to do this properly, get a knowledgeable friend or handyman to do it. It's not hard if you know what you are doing, but easy to mess up if you don't.