Something like this may work. Note the changed door positions so that anyone in the bedrooms can visit the bathroom without disturbing anyone else in the lounge !

It doesn't look like there are any bathing or showering facilities ?!? Just toilets and a basin ?! I think installing proper bathrooms would be #1 on my list ! If you have as much storage a s possible built in and around the apartment - this will give you the modern open feel you are looking for I think !

When designing a small bathroom, plan out every inch of space to its best advantage. This includes positioning the toilet where it will not only pass code but will also be comfortable for the users. The position of the waste pipe also dictates the final position of the toilet. When you plan your toilet's position, take this measurement into consideration as well. Moving your toilet's waste pipe back by 2 inches can sometimes be enough to ensure that your toilet passes code by giving you those 2 inches of additional clear floor space.

What type of advice are you looking for - what kind of western toilet to buy? We are remodeling a similar size bathroom. If you are looking for help picking a toilet, I can post some options here. We wanted one that had a smaller tank in the back but still be elongated. Took us a long time to find one we liked. Most elongated toilets are roughly 17" wide. If you got a 17" toilet with a 24" vanity, that's roughly 3 1/2 feet - leaves you a little room between the vanity, the toilet and the walls without looking too crowded. You could also go with a 21" vanity.