Looking at the 2nd floor plan, the toilet and sink in the bottom right bedroom are right above the dining room downstairs. I assume you've taken that into account for the drain lines? It wouldn't be hard to reconfigure that room to move the bathroom if that's an issue.
It looks like there will be a bit of room behind the pantry under the stairs, potentially a good storage area.
That is the staircase down to the basement. It is confusing how I have drawn it, but that basement door is recessed in there. That wall is bearing all the way down to footings in the basement, everything stacks up that wall for loads.
Basically that L-Shape formed by the two walls on the stairs is the shear and load corner for the middle of the house.
Back to the bathrooms:
those walk in showers require some special treatment. They are ~3" below the floor when you start tiling them, and you cannot cut down floor joists.
You have to support it in other ways. That shower upstairs sits on the midline bearing wall on the north and the 8' long piece of the craft room wall to the south. I will have a footing in the basement and a corresponding wall down there to carry that load.
In order to span that dining room, there is a 6x18 Versa-lam beam across there.
That is poking down below the 9'ceiling by 6"
I will make a drop ceiling box across there ~4' wide and that cures a lot of details.
That ducting chase in the carport entry connects to that and brings the ducting up from the furnace in the basement.
All the ducting for the 2nd floor runs in the joist bays, there is no attic space.
I can 45 my two bathroom runs into that on either side of the beam and take them to the stack, which is located down by that chase right at the end of that beam.
