I don't have pendents or recessed lighting - so no help there, but if you don't have under cabinet lighting, add that to your list. My under cabinet lighting is the most helpful lighting I have. At a guess, I would say 2 pendants over the island, but your lighting store should also be able to help you. It depends on what you use and if your recessed lights light up the island - then pendants aren't necessary. Change out the track light over the sink for sure.

I'm not an expert, just enjoy home decor and design. Your kitchen is beautiful. I have a similar cabinet color scheme, stainless appliances, bronze hardware. I choose bronze hardware and pendants because that's what I'm drawn too. I like the warmth of bronze. I read all the time about mixing metals. I'd suggest keeping the same style though. For example not a modern pendant in your traditional kitchen. Good luck and enjoy.

Good stuff from Beverly above. If you're a visual person (like me) you can also try the balloon trick. Blow up some balloons to be the same size as the lights (as close as possible.) Or you could mock something up with cardboard which would work well since your lights are rectangular (and very cool by the way.) Then hang your mockups on strings from the ceiling. You can play with positioning and length of string to see what you think. Stand by them to check your sight lines when working at the counter, and check them from further away to see how they look. I did this when I replaced a light in my kitchen with a light that has 3 separate globes that can be hung at different heights. I moved my table under the mocked up "light", sat the kids down for dinner, and fiddled around with the strings until I was happy with the heights of the balloons compared to the table. Then I kept the mockup hung nearby for the electrician to follow as a guide.

Loveee that. If you have all that detail on the ceiling I think two will be better. I wouldn’t center them on the island I’d do one on each side. I know it sounds weird. I’ve seen it in real. It’s magnificent