The problem with all of this lighting is that each one is more than likely different color rendering from each other. If you could post a photo of everything, that would really help. Well with 6 inch cans, you can dim them down, and keep them at a certain level. The 4 inch cans don't give out as good of a beam spread and there are not a lot of good choices for 4 inch LED cans other than the Cree lr-4 and a few other brands, but their pretty pricey. If you think 6 inch cans are too big and unattractive, you have ruled out the best lighting choice for your kitchen. Every client that has used these lights loved the looks and performance. http://www.halogenlighting.com/led-recessed.html Mike

Six isn't too many, but rather than locate them in the center aisle space, I recommend placing the centerline of the fixtures at the front edge of the counter. That's how we placed them and it works well. Otherwise, when you stand at the counter you are creating a shadow on the work surface.

There appear to be vents in the ceiling in addition to the lighting; if so that issue would need to be addressed if you remove the dropped ceiling. Keep in mind that any ceiling with beams needs to have the lights below the beams or you could end up with shadows and a room darker than you want. You might consider replacing or covering the existing ceiling material in the same size and shape as your island, perhaps with wood that goes well with your cabinets, and adding a totally different kind of light -- Tiffany style cut glass in a rectangle shape or: https://www.amazon.com/LB72133-Ceiling-Lighting-Antique-Brushed/dp/B018WEOBBO LB72132 LED Flush Mount Ceiling Lighting Oval, Antique Brushed Nickel, 32-Inch 3000K Warm White, 2800 Lumens, Energy Star

We recently put all new LED ceiling lights in as part of a larger whole house remodel. Although not in a bathroom, for the slanted ceilings in kitchen and family room, the GC wanted to put lights that pivot (I think they are called Gimbals). We rejected that and had them install normal LEDs that do not move. The ceiling lights create general lighting, and we didn't feel we wanted more directional lighting coming from the ceiling. In a bathroom your task lighting will be sconces in or on either sides of the morror, or lighting over the sinks. This is a personal choice and the GC was surprised we didn't want the gimbals, but we really did not. Other things to consider are the temperature of the lights. The higher the number, the more cool/daylight the light will be. I prefer the more daylight ones. Also, it's nice to put them on a dimmer so you can control the brightness. I can't recommend a particular brand because the electricians buy them in huge quantities and we went with what they supplied.