With the room dividers, bed can be separated. browse here http://www.theclassyhome.com/comersus_listItems.asp?idCategory=293&Furniture=Room+Dividers

I would recommend a higher bed whether ensemble or any style of base with top mattress or pillow top. I have had serious spinal injuries since 25 (I'm now 40) I would advise any bed reaching around 70cm in height regardless off style. There are a few things that I would advise, overall height around 70cm or a little more, most important to consider is comfort. Do not worry about aesthetics when choosing bed as your sleep is more important to your overall health. So if you can afford the more comfortable bed go for it. As for putting on sheets etc, the weight off mattresses is not really a big deal as it is your sleep comfort that is important. With pillow top mattress with a fitted sheet needing a 45cm fitted sheet are easy to find and purchase from same place bed is purchased. In Australia all bed sheet supplies are available for pillow top with 45cm drop fitted. Percale last longer and are around $100 per set and 1000 thread count. Spotlight have great sales and choices as well as Pillow Talk. I have found Adair's to be quite expensive in comparison but that is up to you to decide. I hope you have many a restful nights sleep. But do not worry about weight of mattress as you need your sleep to live healthy and it is an investment for around ten years so how it looks and weight of mattress should be last on list. Designers may disagree, but our bedrooms are normally our sanctuaries and it is rather easy to make any bed style work for you and decorate to your style.

Before replacing your curtains as this can be quite expensive for such a large window, if they are in good condition, add a band of extra fabric to the bottom in what ever suits you, your existing curtain track can then be moved up to the ceiling for good looking full length curtains without the large round eyelets, could save you a lot of money, I would look at replacing/removing the sheers cheers

It probably depends on where you live. If there are lots of families then i think the 4 beds would be the preference, 3 brms are a lot more common so often 4 commands a premium. An ensuite is always desirable but i would probably just look at converting the linen into another toilet. And create built in storage in all the beds