Thank you for the amazing challenge. I created 2 alternatives in order to give you the choice.
Firstly, I have to say, after reading the briefing, I felt the true sacrifice of the mother of the family to give her sons their own space but asking for a convertible space for herself. (Really moving)
the, as a designer I feel kitchen is not a suitable space to be used as a bedroom at nights. Since no matter how tidy it is it has the smell of the food. Therefore I think living room is a much more proper space to be converted to a bedroom at nights and a living room in the days.
As Always My very first idea for small spaces such as yours is to use it wisely with a lot of storage and no waste of space. I also used your pieces of furniture as well and added some convertible ones to give you the freedom to use them based on you needs.
I included some movable walls in the living room area to let you close it when you want to use it as a room. I included the product websites to find the related projects. Additionally, you have your own closet as the boys closet might not be suitable for you.
For students apartment also I did my best to use the height of room to create 2 bedrooms in a very small area. You have 2 options to choose from.