IMO you do not mix real stone with fake stone and for sure not when the fake is trying to look like marble . Use a nice plain maybe grey glass tile or a white if you can find one that matches the counter or use the counter material for the backsplash

Run the same slab up the wall for your backsplash.

Can you please post pics of your counters with dovestone? We are looking at this or whitendale but can't tell the difference between the two?