In my opinion, a cuckoo clock is a very detailed design, but you say you want a simple design for the room. When you say simple, are you thinking of no wallpaper, no wainscoting, and no accent color on the walls? It seems as if dark orange is a color you favor. I see it in art images and in your curtain color. If this was my space, I would paint all the walls one or two shades lighter than the beige of the sofa to keep the room as bright as possible because the room has no direct sunlight. I would paint the ceiling 1/4 (one part wall color to three parts white). I would use a satin or eggshell paint instead of matte, semi-gloss, or high-gloss paint. I see some discoloration on the wall behind the sofa where the brown color of the sofa frame has worn off onto the wall. I suggest attaching bumper dots or strips on the wood frame of the sofa (similar to the ones used to keep cabinet doors from making a lot noise when they are closed quickly). I would consider painting the sides of the column with the cuckoo clock brown to match the clock. I would do this to call attention to the clock. I would remove the orange curtains and replace them with floor-to-ceiling length draperies hung as close to the ceiling as possible to make the room seem larger and taller. I would change the drapery color to match the walls, perhaps in a muslin-like fabric, which is a casual fabric. I always take my art to a professional framer. I have conservation matting and museum glass used for my art. I would have the three images you have rearranged as a collage in a very large single frame with medium to wide matting between the images. I would have the mat and frame color(s) enhance the images, even if it is a color I might never have thought of on my own. I would hang it above the sofa. I would use the orange drapery fabric to make throw pillows for the sofas. You did not attach a photo of the flooring in the room. A medium tone floor is easier to keep looking clean than a light floor/rug or a very dark floor/rug. Other "Houzzers" will give you completely different ideas. Use the ideas YOU like and enjoy your home!

Dudes, that is a stock image from Dear Kids. That is not the person's room. Dear poster, It would help a lot if you showed readers the colour of the floor, trims, other furniture and even the ceiling. Too, it would be good to know what style of house you have and the other colours in your house. Why people who reply go to more bother than the person who asks the original question, I do not know.

On your paint problem I can't be much help. This usually happens because of damp -- please get a damp expert to make sure that there isn't any damp lurking in your walls. I had this once when I had pipes leaking inside the walls. I didn't know that. The other alternative is something like painting before the plaster is dry or some kind of chemical mismatch. I do know you will have to scrape all the mucky powdery stuff away and start again, at least on those areas. Don't try to seal and prime and repaint until you know exactly what the problem is and how to fix it.

The potential yellowness discernible in Simply White is because it is actually a more colourful white from the Yellow Hue Family. That little kick of colour can work well on ceilings, as that plane can often make a colour appear a little darker & more greyed anyway. So sometimes a choice of more neutral greys here have a possibility of ending up a little grey & shadowy. This is obviously dependent on the available light. Chantilly Lace is a more neutral white from the Green Yellow Hue Family. In character in balanced light it can appear ‘just white’, but in some light people see a hint of its inherent greenness, some might even read it as blueness. Again depending upon how well balanced the available light is. Super White OC-152 is that bit more neutral & so could read a touch more crisp again. Many people prefer a more neutral, crisp trim. It can give you more options for alternative wall colours, should you decide to repaint down the line. Neither Simply or your trim choice would be sat next to each other though, as the wall would come between them. I think the biggest concern would be sitting Simply White next to Classic gray for the reasons mentioned before. If you are set upon Classic Gray then I would repaint the ceiling and swap to one of the more neutral options. I would shortlist your line-up and sample upon board or lining paper in your space so you can move them around.