Sorry but I don't understand your pictures. You are talking about 2 bathrooms but we see only one floor plan. Is the 1.52M x 2.24M the 5 x 8 bathroom in your dilemma title. If so, can we see the floor plan of the 5 x 9 bathroom? Is the space with a small rectangle in the middle the extra 5.5 x 4.9 ft space you mentioned in your dilemma? Also 1.52M x 2.24M is in reality 5'0" x 7'4". This is 8 in. less. It can make a big difference on how to place fixtures in a bathroom.

hi consult with eskandaristone http://www.eskandaristone.com as they will provide you with exact minute details as they are the manufacturer and provides variety of design.Especiality of them is they offer custom design and cut to size. Regards.

Best to contact the manufacturer of this tile.

you can either go for darker grey tiles or a beige. It all depends on how grey your wall tiles are and if they have any underlying colours - are they are purple or green grey etc etc. How does the ventilator affect the look. Do you have a photo?