Why not? The rest of your trim seems to be white? Your carpet and wall color are dark........don't expect a MIRACLE. No to adding the ship lap : )

Yes. They would look good. Try to match the white on the doors.

yes. are the shelves moveable? wall paper on the back instead of shiplap, a textured grass cloth would work, beige or lighter, add some under cabinet lighting & lose some of the symmetry?

i'd consider standing light color posterboard in the back of the shelves just to see how much would be gained by painting/papering just the back. your unit is dark but mostly its dark holes.

you might be satisfied with that much, and not have the work of painting wood cabinets which can chip and look a mess if not done properly. you dont really notice dings in woodwork, and they are easy to touch up. cabinetry requires a different level of care.

I would remove 1/2 the stuff to lighten them up first then match the paint to the trim in the rest of the space but you might find when you do that that the fireplace becomes a huge issue, right now it sort of blends with the wall so maybe just paint the back of them and see if that works.

I usually dont recommend painting when you have nice looking stained wood, however, yours looks a bit dark and dreary. Could it be poor lighting in your room? You could paint them, as long as you use the same color as the trim, but, then, I am wondering about your rustic looking fireplace (which I really like). It may just look way out of place, once the cabinets are painted. Maybe try the poster paper in the back of each shelf,and see how that looks. If it looks good, then maybe just paint or wallpaper, the back of each shelf. You could also put some lighter, brighter objects in there too. It looks very dark and dreary in those shelves right now. Maybe even some type of lighting put into the shelves themselves??? Some type of lighting that would mount in the ceiling angled directly at those shelves. A nice cheerful looking area rug in front of the fireplace, with maybe even a couple of chairs on each side of the fireplace with tables by each with a table lamp on them. The wall paint has muddy tones to it, so the whole part of the room, we can see with your picture, actually looks a bit gloomy. If you do decide to paint them, make sure, they are scrubbed well, to get all furniture polish etc off, and sand them very well, and prime them with a good bonding and sealing primer, and then use regular cabinet paint in the same color as your trim on them. Personally, I would try, other things before painting them, because thats a lot of work. :-)

True, it is a lot of work. But here's a similar situation as grist to the mill:

I'd use the same color as the trim. Failing that, a white that looks deliberately different from the trim (so it doesn't look like a bad attempt at matching..

Don't use standard latex semigloss. Everything will stick.

No to shiplap.

Looks great!

yes, I think white would be a huge improvement!

Looks much nicer.

Nice! Now how about some nice hardware for the doors?