Your best answer to your different configurations is to contact a dealer or the manufacturer itself and ask directly about any changes you might need.
Also, don't rule out that you won't need those two extra chairs. You have two dogs, don't you? They like to look outside, too! :)
Small RVs sometimes have what they call a 'wet bath'. Indeed, if taking a shower EVERYTHING gets wet, including the toilet, toilet paper, towels, etc. So you'll have to do more preparation in protecting things when you shower. A separate contained shower would be much better.
You mentioned the bed that comes down from the ceiling. This definitely wouldn't work for us as we have different sleeping habits. If one can't sleep or is up with a cold or other medical problem, you'd be disturbing the other person trying to sleep. The same would be true having the sofa turned into a bed. You'd both have to retire at the same time and will be waking at the same time.
Good luck in finding the RV just for you. It's out there!