Hire the architect that your building requires and recommends.

I'm not a fan of the wall-less effect. I live in an apartment that has an archway between the dining and living rooms, and I love that the wall of the archway interrupts you view as you look from one room into the other. That change in perspective makes the rooms seem bigger.

Other people in our complex with the same footprint have removed that wall completely and they brag that it opens the space up and they think it makes it look larger. Every time I'm in one of their homes, I think, "wow, this seems smaller than ours."

I would consider at least a half bath, if you can actually do it.

And I also think some sort of entryway makes a place feel larger--a transition space of some sort, even if it's a corner of a room.

Thank you for your comments! what do you think about this plan? do you see any improvments or possible changes?