My downdraft is great with outside motor so not too noisy. Having said that I would also have been happy with a ceiling extractor if I had the space above for the venting.

I think the only way you can do that is to swop the positions of the oven/range and the storage drawers. I'm sure it's doable, but there might be practical problems.

It's definitely more centered than mine is! My house was built in 1945 when stoves were a lot bigger and that's why my range hood is bigger than my electric stove. Anyway, when you put up your floating shelves, you can either make the left size longer and the right side shorter. It will work that way unless you want symmetry. Then, I would suggest you make the shelves the same size and put them up in the same position on both sides of the range hood, just like a mirror image.

Can't seem to get greasy marks off a stainless steel range hood