I think the basket is too wide and bulky for that space. I also think you should do what makes you happy. If you love the basket, put it up! If you feel the need to put something in that space, it should be rectangular, hung the long way to fit the space. Maybe you have another place for the basket. You did not ask for comments about your pictures, but I will say they are not too high. However—The bottom of the bigger picture should be level with the bottom of the smaller picture. One is a little higher. If the big picture is hung with a wire, you may be able to loosen the wire a little bit and lower it down.

That looks like a light I would expect in a hotel or other commercial foyer. It is way to big for any area I see in your photos.

I'd call another tile guy. We see kitchens with marble tiles used as backsplash all the time. I used 12 x 6 pieces of marble tile on painted drywall 10 years ago and not one problem. Behind kitchen sink, installed with mastic.

If you do replace the counters, consider adding more space behind the sink by a few inches (6"?) to reduce water splashing on the floor. If you're planning a seating overhang, then 15", at least (18" is better when behind a cleanup sink). Just be sure you don't get too close to a table, if there's one in that space. You should have 54" to 60" b/w table seating and counter seating that has at least 15" of counter overhang (if less than 15", then add the difference b/w the 15" and the actual overhang to the aisle space -- people take up the same amount of space in the aisle with or without the minimum overhang, they're just more uncomfortable b/c they have to lean forward so far, so you need to account for that "extra" space).