Just a quick suggestion, if the plumbing works place the WC under the staircase. And place the door so it does not open towards the living or kitchen areas. Please also post some photos of the house as it looks from the outside.

It would help if you post an existing floor plan with your sketch of what you want to do.

I would definitely go for a larger kitchen therefore a swap. Also if structure allows to remove this little bit of unnecessary wall by current kitchen entrance would make the space more open.( I think in the other plan I see it is happening?) the outside door swap for a window is a very good idea in my mind.

We will have oak trusses also. I want to have a lot of natural materials inside.