Greys would look good in these rooms. I wouldn't paint the paneling. Rather than a mirror over the fireplace a large scale painting would look good.

I think the first layout is fine. You might want to consider moving the door for the storage room of the master bedroom so that it opens into the hall. That way the kids can use it for overflow storage. Also, that hallway is big enough that I think it could hold a large armour, providing more closet space. (There's no need to sleep in the same room as your clothes, so long as they're not too far off.) Also, don't forget that while the drawing shows kids in double beds, this need not be the case, so there will be more room for furniture (dressers or whatever) in their rooms. Finally, that step to bedroom 4 will not be odd at all. I've seen it in other homes. It looks clumsy in the drawing but it isn't. What you'll see when you come up the stairs is a bedroom door on a slight diagonal. It's only an odd jagged step if you walk like a robot, in straight lines along the wall, which is what your eye is doing on the drawing but you won't do in real life.

Thanks :) Yeah decided to go with tile. So sand cement is ok over existing tiles if I prep them first? Only problem is, the new pad can only be about 30mm at it's thickest (leaving up to 15mm for tiles) otherwise it'll end up being higher than the hallway floor. So I either need to make the fall shallower or not bother with the waste and make it all level. If I made it level, could I use levelling compound at that thickness or would deck mud/sand cement be the best option? Also, should I be putting in mesh for strength? (I know I should (and will) ask the local hardware what they suggest, but it's great to have suggestions from the Houzz community also)

We have a 900x900 shower and it's plenty big enough. Neither of your proposed layouts looks that great, to be perfectly honest, sorry! In the first layout, you could improve it quite a lot by swapping the toilet and vanity (centre the toilet under the window on the bottom right of the picture if possible), and having the shower door on the other wall (beside the door). Then, you could have a towel rail on the wall beside the door (i.e. behind the door when it's open), which would be accessible from the shower but hidden when the door was open. An 800x1200 shower might be a good size for your space. You'd have to choose a toilet that doesn't protrude too far, plus a narrow vanity. With that layout, you could have a long but narrow wall-hung vanity, with a big mirror covering the wall between the windows, which would make the room feel bigger and would give a good amount of storage. Also, you may find this helpful: http://www.houseplanshelper.com/small-bathroom-floor-plans.html?utm_content=buffer4aa20&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer