So, I've followed with my own suggestions and came up with an alternative.
Aerial front.
Aerial back.
Floor plan of the basement apartment.
Floor plan of the main floor.
Floor plan of the top floor. I didn't make any changes to this floor.
Floor plan of the attic.
I've opened up the "Underground area - Support only", mainly because it seemed a waste of space and I didn't believe the house needed a support like that. In doing so, I moved and enlarged the laundry room, and have been able to add both a second bedroom and a small storage area (or extra room, however you want to use it).
On the Main floor, I took out the sewing stuff and moved it to the attic, and in so doing made this room into a proper bedroom. So this version has two guest bedrooms (or one guest bedroom and a "maid's room", also however you want to use them).
In the Attic, I used the closed off area for the sewing room; much more space for more storage. The rest of the attic is open for either more storage or however you want.
I didn't change any of the garage or the storage area under it, so I didn't take any pictures of it.
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