I want to install stair guardrails in the steps of my front porch. I have five steps, so each handrail will be about 6 feet long. I want to install 2 newel posts at the bottom of the steps , top and bottom rails with balusters, which will be attached to existing upper posts on the porch. The steps (and porch floor) are concrete with a flagstone fascia

I want to use 6x6 newel posts (to match the existing posts). Is pressure-treated appropriate? If so, can I surface-mount the newel post, or do I have to embed them in fresh concrete? In theory, the newel posts will be attached to the top/bottom rails and balusters, which themselves will be attached to existing posts -- so it's not completely free-standing. But I don't want the rails to wobble. On the other hand, I heard that embedding PT posts on concrete will eventually lead to rot due to the moisture trapped in the concrete.

If surface-mount is good enough, are there other alternatives to PT? Some cellular PVC or polyurethane?

Finally, if surface-mount, can I drill the concrete/stone fascia with a regular masonry drill and hammer drill? Or do I need to get one of those diamond drillbits and lubricate with water, etc?

Thanks