"I want to update the tiles with tile decals. " In front of a fireplace? Looks like you use this fireplace, and you expect decals to last exactly how long?

Hi there - I am going to say few things that will make me sound like the bad guy, but don't kill the messenger. It appears you have a standard wood-burning fireplace in a manufactured home that has had unvented gas logs added. Assuming my powers of observation are correct, there are a few things you should know. The stone wall panel is probably only held on with about four screws. If you look very carefully between the joints in the stone, you will probably find where the screws are. You can probably just unscrew the screws and take the whole thing off. You'll have a blank slate! If nothing else, you can take the panel out to the garage or yard to experiment with colors without worrying about making a smell or a mess indoors. If you wanting to paint it, I'd start with a block primer, which will help to deal with the porosity of the stone. Otherwise, it will probably be three coats of regular latex primer. A good semi-gloss latex paint is the best thing to use around a fireplace. It handles the heat better than solvent-based finishes. Don't paint the hearth, no matter how much you are tempted. If you don't like the color, replace it with another non-combustible material. Also, FYI, if you look in the installation manual for that fireplace, it was not approved for the installation of unvented gas logs (those kinda look like Temco Amercan Dream logs to me, but I could be wrong). Technically, you can keep the logs, but the damper must be clamped open, which means they won't heat the same way anymore. Running the logs without the damper open could create a hazardous situation. The heat deflector hood should not be covering the upper louvers. It will prevent air from circulating around the fireplace, which creates a potential hazard. You will not need the hood if the damper is open. Don't run the gas logs with the glass doors closed, in case anyone forgot to tell you. Hope that little bit is helpful. Happy re-decorating!

Pleasant looking room. You might experiment with different colored bulbs for your ceiling/spotlight and find a light that could be more of a whole room light than either your spotlight or ceiling fan without being s glaringly bright when you don't need that much light. There are floor lamps with two lights -- one lights up the ceiling (conversation lighting) and the other is flexible/adjustable (reading light). Using less intense indirect lighting instead of the spotlight or overhead light could give your room a more relaxed and comfortable vibe. https://www.amazon.com/Floor-Lamp-Light-Accents-Torchiere/dp/B0085NX9B6

To my eye the fireplace does not have attractive proportions. The hearth is too wide and and overly deep for its height, the wood box is too small, the ceiling trim too bulky, mantle too large and too high. And the doorway looks squashed in beside it. No amount of whitewashing or painting is is going to change any of that. The good news is that it looks like the stone isn't boulders stacked up like some of the photos people have posted above. I think it's rock veneer, flat pieces of rock stuck to a cement/wire mesh base. If it's veneer, you should be able to see that from the side. Can you stand by the round mirror and take a picture for us? Veneer can be removed relatively easily by someone with experience and the right tools. Then you can have the room you want. You can shorten the hearth and put the TV to the left of the fireplace which would look much better than above it. Now is the time to do it, when you're re-doing the floor. If not, be sure to keep a box of the flooring for later if you want to remove or shorten the hearth and need to fill in the floor. My house also had an overpowering stone fireplace and the best thing we ever did was replace it with a normally-proportioned fireplace surround. IMO these large stone fireplace walls look great in big chalet-style homes with high ceilings, and are out of place in regular homes.