The last idea is actually nice: a smaller tub... Imagine if the walls of the tub were higher to the point where if you say down with your knees to your chest in the tub, the water could go up to your chin. That'd be a nice place to just soak.
The plan is to create alcoves in the kitchen-diner by building a false chimney breast. We'll then have symmetrical dressers in the alcoves and an electric wood-burner with fire surround. Image from Dunham Fitted Furniture