Is your desire to create square lines as great as the expense and headache of reworking the cabinets, countertops and floors? Will you draw a floorplan of what your contractor is proposing?

What about a bigger sink?

You are planning to get new cabinets and countertops in order to do this, right?

Once the cabinets are moved to be square, when you plan countertops, I'd plan a shelf behind the sink, made from the countertop material- a plant ledge/shelf type concept.

Eight or nine inches behind? A gift! No worries

i might ask what is left out of sight in your pictures?

Take some more- other angles and add in a comment box below.

Oh I think you’ll love that space behind the sink! Easy to wipe clean instead of squeezing your hand between the faucet and the wall. A few plants or something. It will be nice :) If you’re by chance replacing windows you could also consider having them go down to counter height and extend the countertop to also act as a windowsill.