We are working on some improvements to our kitchen. We removed laminate backsplash near the sink and behind the counters on the opposite wall. We also removed a cabinet that was above the sink that we didn’t like. Now the question is how to prep the wall for improvements. We hope to put new backsplash on the wall by the sink. And we hope to simply paint along the wall behind the counters on the opposite wall/where the cabinet used to be. Some areas are pretty torn up from the backsplash removal, and I’m wondering how to repair? The walls in most of the house are plaster, but I’m wondering if the wall with the hole in it by the sink is drywall? Photos below. Any advice would be much appreciated.