Traditional, pieces on top are flush or slightly narrower than the "base". Think of the mirror and vanity set-up like a hutch sets on a buffet. For single sinks, flush might be better for functionality; the mirror ideally wouldn't be narrower than a person's shoulder span. For a longer vanity..set the mirror in some if sink placements allows...like 2" or 3" per side- feels more like furniture pieces and will draw the eye in.

Not sure how much space you have between top of headboard and ceiling, but you could do several prints vs 1 large print, or skip the artwork all together above the headboard and place 1 or 2 prints and/or even a mirror above the nightstands. ( if you have)

First you must consider height as well as width, you dont have cathedral ceilings, that fixture looks about 24 inches long, which means with out any chain it would hang at an 8 foot level. Second, fabric shades and kitchen sinks don't mix, trust me when I say water splashes in all directions! plus steam from hot water can all mark the shades. your kitchen is small so I would not close it in with solid state drum shades. I would do 2 larger scale glass pendents. Use the drum shade in the breakfast nook.

I think it depends a lot on personal cooking style. In my case, I realized that it is impossible for me to actively work on more than two pots at the same time. The remaining pots will always just be simmering or kept at a constant low temperature. You can of course do this on a big stove top. But a professional chef at some point told me a secret. You are almost always better off doing this in an oven instead. Much more even heat and less risk of scorching your food. I tried this for the last couple of years. And yes, that person knew what they were talking about. Turns out, having multiple smaller ovens is much more valuable than having another couple of hobs. So, when we remodelled our kitchen, that's exactly what we did. We also made sure to include a combination steam oven, and it can do many of the tasks that you would normally do on a stove, and actually do them better, faster, and easier. I find, these days, I use the stove much more rarely and when I do use it then it is mostly for stir frying. That's a fast process that needs my full attention. So, again, all I use is a single burner. But then, on the other hand, there are people who regularly cook for 10 or more hungry mouths and who cook large quantities of sauces at the same time that they have a few pots of freshly made jam and a big pot for canning vegetables. If that's what you do on a regular basis, then yes, you probably are one of the few households that does benefit from a 48" range. To a lesser degree, the same argument can be made for people who regularly use their flattop or their indoor grill. Discussion on Houzz has shown, that relatively few people actually end up using these tools regularly after they bought them. But yes, there are some households who do so. And if you are one of these, then you probably would enjoy a bigger stove area despite all the extra costs in space, money, and planning. These days, I don't try to discourage anybody from getting a big stove. But I do try to understand why they believe they need one, and I try to explain the consequences (positive and negative) of this decision.