The cans spaced 3'-4' apart is certainly tight for "relaxed-living" rooms (vs kitchen). You will first need to map out the ductwork, or use wafer lights to fit under. Am I understanding the ceiling height is 6' under the ducts? Minimum is 6'-4" for usable spaces under a duct.

Existing toilet position and how that line ties into the stack, assumed cast iron, may influence a lot. Any basement bath layout usually depends on how much demo of the slab your wallet or back are willing to put up with.

If you are laying out new rooms except for the Library+Mini-Library, I might try to group Family with Libraries and keep Workroom away from them (back fireplace and what the Library actually does notwithstanding). Also FWIW once a bed is put in the Office, the room needs an escape window.

It's not a good idea to have a bathroom entrance in the family room. The bathroom door shouldn't be located where family members are gathering, i.e dining rooms, family rooms, kitchens, etc.

In any case if you leave the bathroom where it is, I would put a toilet next to the vanity you have plenty of room to push the shower wall out if you need extra room to fit everything and make the shower at least 36" deep.

Here is another layout with a few changes to give an idea.

Thank you, 3onthetree and G.N. Builders. G.N. Builders, your idea for the bathroom is very good. I will definitely consider it. The plumber we hired will have to break concrete to add a shower to the existing bathroom, and he said that once it’s done the toilet can be moved anywhere we want to, no extra cost.
3onthetree, so you are thinking I am placing too many lights in the office? Library? Just for general lighting, how many would you put in? We might use the office room as an exercise room, so there would not be any additional lighting in that room.

Thank you again.

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.

Thank you, kandrewspa.

Yes, I am planning to use dimmers on all switches. Re furniture placement - we are not planning to use the basement much. We are retired, our children live on their own, and we have a large house for the 2 of us. We decided to renovate the basement while we physically can still do it. We hired all trades, and are coordinating all work ourselves.

I am still playing with the design - I enjoyed learning House Designer Pro software and laying out the basement. It is an easy program to use and is very good.

Thanks again.