I have scratched my bench top with my pants' metallic button just like that. Before realising what it was, I was wondering if my son had been naughty. Bar keeper friends stone cleaner does wonder to those marks.

Personally I'd be very careful adding stacked stone next to the dark bricks. I think stacked stone can work next to rendered areas to provide contrast/add another element but next to dark bricks it could easily look too busy/too much. It's your home though so do what will make you happy when you drive up to it! If you're dead set on the stacked stone then find the brick manufacturers location and ask to speak to one of their designers for an opinion/options. If they can't help then ask brick manufacturer for the addresses of some properties in your city that have used your particular brick and check a few out. They will usually give you some addresses if you explain what you're trying to do. I'm sorry to have not answered your question as to what colour stacked stone to use. Good luck, exciting times for you.

I wouldn't go those dark laminate kitchen cupboards. I have the exact same and I absolutely loathe them now. I use to love the darker colours but now I wish I had just done them white, light gray or even the dark blue (although dark blue worries me a little too!). That dark laminate brown is such an absolute pain to keep clean. They show up every mark. I like your stone bench tops though but would look at other options to create the look you're hoping for with the joins and waterfall benches etc. Goodluck with it all!

the black marble with white stone veins through it. the picture you uploaded seems to have a name of milky way on it.