You need light and bright. Being rented is tough. First change out the drapes with to the floor length. Cream with a horizontal stripe of brown to match or furniture. This will 1. get rid of the horrid things hanging there 2. pull the initial visual to that wall instead of the floor. Tall and high colors ( mango, aqua, yellow) decorations on your mantel with shorter cream and brown items. Then a large square table in the middle, painted distressed cream, with high color items setting on it. DIY project or Ikea. Green is the number one calming color, just don't let it put you to sleep. :)

A company or contractors who install radiant floor heating might be able to help you. The idea i have is this : An electric heater that hugs the underside of the granite. Granite though is a dense rock. How thick is it. For a bench i'm thinking at least 1.5 to 2 inches. It might take a while to heat up though.

I think what you have done is amazing - so fresh and so modern - it is a great example to people like myself who have an old kitchen with good bones but no longer modern. So many people spend far too much money ripping out usable kitchens, that function well but they think they need to get the new and latest, often just to keep up with the "Jones". You have done an amazing job without the huge cost of replacing all your cabinetry. WELL DONE.

Is your stone veneer to be laid on a slope? I would want to see an example of that beforehand. The stones in a sloped wall are still set horizontally, but the veneer will have joints that look skewed if laid sloped so it could look quite odd.