The gloss black bench top - (countertops) will be a bear to maintain. Black will show every crumb, water ring, and reflect the bottom of the cabinets. I would do a grey counter top and then darken the grey for the backsplash. Over the cooktop I would insert a pattern of tiles to offset the area using maybe some black grey or even red checkerboard pattern. The red would bring in the color from the pendant light. On my Houzz site I have a kitchen with dark cabinets and black granite counters and checkerboard 1x1 travertine. There is a contrasting inset above the cooktop. You might look at it and see more clearly what I am talking about. I would do a one color backsplash with the cooktop inset the color / contrast in the kitchen.

I debated long and hard about having a gloss black benchtop in the downstairs kitchen which serviced the entertaining area down there a couple of houses back but went ahead and never regretted it. It wasn't difficult to keep clean and didn't show water rings or crumbs (any more than any other benchtop). I had soft green cupboard fronts with black handles and designed it to look like a 50's diner. Space was tight and long so it was a narrower galley style than one usually sees but I swear it was the best kitchen to work in with lots of practical (black) bench space. I really loved it and miss it and wish I'd taken photo's.

I love those pendants, quite delish, they'd have looked great in my 'diner'.

And you might tire of the checkerboard, I did in one of my bathrooms. If you're like me and change everything around every few months and are always thinking about what you can do next, don't do checks they'll drive you crazy.

I just had another look at you kitchen plan and had a couple of thoughts. Have you considered that the pendants won't give you enough light when cooking and working at the sink bench? Plan some recessed lighting underneath your cupboards, they're not visible but make a world of difference.

Where are you putting your kettle and kitchen gadgets that stay out all the time, there doesn't appear to be a space for them? I'd move the sink more to one end of the bench rather than in the centre to create more bench space. It will mean you move the drawers next to the dishwasher and the cupboard towards the end where the sink will be.

I'd also think about the sink you choose. Get a large bowl that will take your biggest dishes/roasting pans that won't fit in the dishwasher with a smaller strainer type alongside. Don't go for a round one they're impractical.

Get more power points than you think you'll need and don't forget to get some put under the island bench, I think you'll be needing them. What an exciting time, have fun!