Thank you for the amazing challenge. here is a virtual tour of your house
I created 2 alternatives for your plan in order to give you the choice. The first alternative is based on clean separation of the day and night area and open space for the kitchen. However, as you mentioned that you might not be able to change the gas pipes, I created another alternative which I created the renders based on that.
In the first alternative though, you have bigger bedroom en-suite bathroom and guest bathroom too.
Hope you enjoy.