[Highland Park] recommendations for wall restoration post mantel & mirror removal

In anticipation of installing a new gas burning fireplace, I removed the existing mirror, mantel and tile. I now have a hole in my living room which I'd like to close/seal up and finish as just a wall. I'd appreciate recommendations for how to do this and contractors or trades people to do it. A few have suggested refinishing it with plaster, while others have suggested drywall. The existing original baseboards and missing hearth area might be complicating factors. I have original pine floors that have been refinished. Any advice or suggestions would be appreciated. Thanks so much.