A picture woulld be helpful. Is this a full bath? Master bath? It sounds like you are limited on the size of the fixture due to the depth of the soffit --- maybe 11-12" at most? Would it work to use a track lighting fixture?Here are some examples. We used one in our laundry room to try to get more from the single small fixture there. Is this over the vanity but has to light the entire room? How large is the room? Is there a way to add any other lighting -- wired, plug in -- any thing? Is there a power vent in the center of the room or near the toilet (is that in the same room?). You, can get a vent with a light or light with a vent, as the case may be. Don't get to scrimpy on the lighting. Even if your budget is tight, it is important to have proper lighting.

You don't HAVE to choose two matching fixtures at all, especially if you like the atomic ceiling mount better (I think it's pretty nifty myself). It goes well with the icy glass vanity lights without looking too matchy-matchy. I say go for the atomic one!

I consider myself something of a color expert. With your tile color, I would stay away from pinks. The best color for you will depend on if you like the tile color and want to contrast it to make it appear more green, or if you want to make it stand out less. For a little bit of complementary contrast, try a sample of Ben Moore's Dreamy Cloud which is a light purple grey with a light reflection value of 77.92 which is nice and light. In the pic, it looks like you mainly use artificial lighting which makes it a warm green rather than a cool green that it would be in natural light, so for less contrast, I would go with a light warm green like Ben Moore's Palest Pistachio. It's a beautiful green but very light which will help the room appear larger and brighter and should make your floor appear less green. The LRV is 85.64, which will really help if you need the room to be brighter.

If you're redoing the shower anyway (looks like tile and grout are degraded and may not be keeping moisture out of the wall), then a tub is pretty cheap, and you might be glad you replaced it rather than having to build your whole bathroom around the current shade of gray. Plus, it may look even worse once the rest of the room is fresh and new.