My house and bathroom are small so space saving is critical. The original old bathroom layout has a small square shower and a separate half bath, with an even smaller basin right next to the toilet. It was claustrophobic and the half bath was only used for storing cleaning stuff. When we renovated, the bathroom was gutted, keeping most of the original plumbing points. Though we are not "bath persons" we decided to have a shower over (normal length) bath with frameless swing glass screen. From past experiences, I find it easier to clean a shower-over-bath than a fully tiled shower area, or one with a shower base. When visitors with young children came to stay, having a bath was handy. Combining shower/bath gave us room for a long vanity with plenty of bench space and away from the toilet. It now has ample of space in the middle for changing and moving around each other. Shower-over-bath definitely is an efficient use of small bathroom space.

Hi, unless you take a bath at least once a week I'd skip the tub. I'd rather enjoy a bigger walk in shower, which is also a lot safer than climbing into a tub to shower. If you have the space instead of a tub and shower I'd consider a double vanity to give you extra storage space. It's a little luxury you will come to enjoy when everyone is getting ready on the morning.

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

I can't see a problem with the drain. However Depending on the bath, he bath to walls requires " waterproofing "to some degree, to prevent water from pooling under the bath