Ask your contractor if the water heater and furnace (?) can be moved into the lower right corner of the utility room. If so, I'd have him frame them in to a utility closet, leaving the rest of the room open to create a guest bedroom. That said, if this is going to be an oft-used guest space for sleeping, you're going to need another form of egress to meet code. Have him add another window in the bedroom area and make sure the window is large enough for someone to get out of in the event of a fire.

Hi Mat, You’re right! Working around a staircase in the middle of a basement is tricky! So is the 22 foot long shuffleboard! We would love for you to look through our photos to get some ideas of how we have incorporated these things in our past designs. We have blueprints, 3D images and completed project photos on our Houzz page and our websites. We can also help you complete your design in 3D if you really want to feel out the space before you start building. I hope when your project is finished it is everything you want it to be. Finishing a basement is fabulous investment for your home and family. You are off to a great start!!! DYB Houzz

Again, you could fill almost half of the fireplace area with window bench, game table and chairs like here ...? The walk-through function has essentially decreased the size of that area- and fp is to the side also - I think furniture or most of it can be in front of fp, and the window. A 'wall' might start with drywall to right of window - or measurement at which fp is [from window wall].

You may have already thought about this, but dimmer switches will make whatever lighting scheme you decide on more flexible. Also, think about where furniture will be before placing the recessed lighting. 18 months ago we moved into a 25 year old house that had a finished basement (also with some windows, like yours). While they at least had dimmers on the recessed lighting, the placement of some of the cans was puzzling, even considering where they had their furniture when we saw the house before purchasing (the previous owners did the basement fit-out). I like the one room that has cans in the four corners and a central fixture which is a semi-flush 3-light (the cans are placed about two feet from the walls). The result is that the room is lit very evenly without the use of any table or floor lamps. I use the room for an office so I have a desk lamp for task lighting. Even if you don't use the other part of your basement, if you finish it so it could be used for a family room it will be good for your resale value. The next owners may want to put their teenagers down there with a big television. :-) I love the idea of the full bathroom. That is something I don't have in mine.