I would get an upholsterer to do a couple of long foam cushions for the seats - colour would very much depend on the rest of your home, but teal would look good there (and so would navy).

We would recommend using the same timber as the floor if you can. This would make sense and keep your material palette as simple as possible - there are some fantastic timber finishing treatments available that will provide a durable surface that is easy to maintain. There may be a way that you can introduce a separate timber element say 40-60 thick that sits on top of the existing solid top... perhaps a bit like the kitchen in this image by 'Beef Architects'http://www.contemporist.com/2013/06/21/riverpark-apartment-by-beef-architects/ap_210613_07/

stone in kitchens is an easy surface to have in a high traffic zone - The Marble Man repair, polish and seal stone surfaces - when you make your final decision have a think about the wear and tear of the bench tops - give our office a call for our professional stone services 1300 627 626 | The Marble Man

I've long been concerned about the formaldehyde in laminates, which also continues to outgas after installation, but until recently questions about it were met with a blank stare. A few years ago I was pleased to see a sign in the kitchen section of Masters making a claim regarding that (I think it was the first time I saw the E0 rating?) but when I asked for information about it no-one knew what it meant and eventually they suggested I talk to their 'supplier' which turned out to be the hardware supplier who knew nothing about the laminates. Very disappointing when retailers of better safer products fail to take the opportunity to educate customers and promote those products. Good on you Anne Marie for wanting to ask intelligent questions. (I could start a whole new thread....)