We have a safe room in our almost finished house. It has cinder block walls reinforced with rebar and poured concrete. There is also a steel door that will have a panel on the front that looks like the other doors in the house. It was important for me to have AC/ventilation, lighting and an alarm pad inside the room. There will also be a big lock inside (that the kids can't activate) to also make it a "panic room". There is plenty of room inside to store essentials for a few days in back packs in case we need to evacuate. I'm thinking I'll store some type of fold-up seating in there. Sitting on a hard floor for any period of time is not fun. I had a photo of the construction of the room, but can't seem to locate it on my computer. Here is a photo of the outside - all you see is the steel door.

I'm assuming the wall between the kitchen and living room is load bearing. If that is the case you can install an LVL (laminated veneer lumber) or steel beam as long as you have column supports at each end. There's not much to be done about the stair unless you can move it. If not it will continue to act as a divider between the living room and kitchen although at the upper end of the stair the division will become less as there will be more head height. This might allow for moving the living area to the end opposite the entry and garage door and creating an "L" shape. That would require moving the powder room also. Hard to make real determinations without seeing more detail plan or seeing it in person. So, take my comments as generalizations. Good luck!

That really leaves you with the current arrangement, replacing the grey chair by the front window with kid stuff and leaving the floating living space opposite the TV. I'd really look into rerouting cable so the TV can be where the large art piece is. It's not usually very expensive and will be necessary in order to keep your walkway from running right in front of the tv.

Honestly, don’t waste your time and money on this apartment. Anything you add will be on your $ and with 3 dogs and a temporary room mate, I wouldn’t invest in anything.