I think they mean 5 rooms, not 5 bedrooms.....one master bedroom and 2 bedrooms for children with twin beds or bunk beds in each. I lived in a 1,300 sq ft house for 2 yrs with my husband and 2 sons. My suggestion would be to have an open floor plan for the kitchen, dining area and family room in one large room. Add a bar in the kitchen for casual dining. Be sure to include storage in family room for toys, games, etc. Add a built in desk in eiher the kitchen or family room areas . The master bedroom and bath should be large enough to accomodate a queen size bed and if possible a sitting area (maybe a bay window large enough for for a small loveseat or a couple of comfortable chairs). I would recommend a large walkin shower but no tub for the master bath. Instead have a nice size tub/ shower combo in the hall bath. Too make your house feel larger, use neutral camel, beige, gold or grey paint and carpet through out the kitchen, dining area, family, hallways and hallbath. If you want to add color, limit it to 3 bedrooms. Hanging all your window treatments at ceiling height will make your rooms feel larger and taller.

If the door is well painted I doubt if you will have a problem. A good coat of paint on wood work and wall surfaces is important if you have a lot of moisture in the room. If you can do some alterations to the space I would suggest you install an exhaust fan in the ceiling that vents moisture to the exterior, i.e. through the roof or side wall. Companies like Nu-tone and Broan make fans that have a moisture sensor that will kick on the fan while using the shower if you forget to turn it on. And these fans can be much more quiet than the typical bathroom fan. Some hundreds of dollars for the purchase and installation of this would be well worth it. I have seen bathroom ceilings covered with mold because the room has neither a neither a fan or window so you are right to be concerned.

@sooz001 - Top frame weather shade is same as bottom one. Attaching new pic for better view. Mostly, i will have to use wooden shutters and extend the weather-shade, may be using some stone or RCC.

It’s is back painted glass. As a back splash it can be used as it’s easy to clean and maintain. Highly recommended to be toughened. The entire back needs to be cladded in waterproof plywood and then the glass is stuck on to it with special adhesive or silicon gel. Any reservations on using plywood then you can opt for WPC ( wood plastic composite ) which is alternative to play and is totally termite-water proof.