Manhattan42 - sometimes you say the craziest things. In my neck of the woods, every crawlspace is vented and unconditioned. Sealing crawlspace is a new thing but even then you don't purposely heat the space. There is R-19 under the floor - that does a pretty good job at keeping the heat in the house. Are you in NY? - if so it is possible that your codes are more like the OPs. But around here in crawlspace land - we vent and don't condition. Sealing costs some $ but does help some wuth heating costs. To the OP - you probably have a basement - so all this doesn't apply. Yes - you could heat the basement. This helps but tile is still cold and it is nice for the bathroom to be the warmest room in the house when you shower. We use supplemental heat on our 2nd floor bathroom. It really sounds like heat lamps or fan heaters are what you want. They both cost the same to put out the same heat. You can only beat that if you have a hot water heating system and can tap into that. Having had both - I prefer the fan because of the "baked" feeling of heat lamps. The lamps can be directed better for heat in one particular spot but the fan heats the room better. My father is a PhD engineer who wrote some pretty landmark papers on energy efficiency in the 70s - he agrees that using electric resistance heating in a bathroom for occassional heat is the way to go. If you use it for 5% of the time, it doesn't really matter that it isn't the cheapest way to make heat.

I have thought more about this. Like Beth said, you could really get a lot more in that bathroom with only one door. I think I drew what she suggested. As far as the door between the two areas, I think it could go either way, but if possible, I think a pocket door that slid into the area by the tub would be better. This would keep the door from being in the way and be almost entirely hidden if not in use. I had one additional thought as well. Assuming later down the line there are additional children or the house is sold to someone with more than one child and bedrooms 3 or 4 are used as bedrooms. Is it going to be fair that the bathroom opens into bedroom 2? Seems like that might cause some disagreements. On that same thought process, the one thing that might bother me would be seeing into the bathroom from downstairs. Although this puts you right back in the same position having bedroom 2 walk around the corner to get to the bathroom, the view from below will be nicer and access will be more even between all 3 bedrooms. If doing something like this, I would extend the vanity the entire length of the room for plenty of storage underneath. (This is the placement of the bedroom door from your first drawing.)

To answer your ps: Sophie is Sophie Wheeler, a very long-time pro who was a prolific poster on this website since before it became Houzz. She was incredibly knowledgeable about everything design/construction, and tried her best to knock some sense into people. She was funny, smart, and just seemed to know everything about everything, so she was widely respected for her knowledge. She wasn't universally well-liked, however, due to her direct sharp nature. She was banned from the website, but I don't think it was over her direct bluntness....since there are several pros and others still here who are at least as direct, blunt, and sometimes offensive. A lot of people were offended by the way this website treated her, and some people left, never to return (apparently). I'm sad she left, and sadder to hear that she is in poor health. I believe you can do a search for her name, and read through some of her comments. It's a good way to learn a lot about building a house and remodeling, without making horrible mistakes.

Sativa has a good idea for a high contrast design but I might be overwhelmed too much dark black. It would need the balance of lighter floors and the natural light from the windows which could make it stunning. I bought the same pebble tile at our local H H Restore to re do our tiny shower. I want bright white tile like your subway tile but hubby still wants a large format porcelain. The mix from the pebbles can work with many things. Remember when it is sealed the colors will deepen to what it looks like wet. You could use a midtone like the charcoal grout for your floor tile if you are keeping the walls lighter like a warm white, tape or grey from the pebbles. If you go with dramatic black walls, you need a lighter grey ,taupe or warm white for balance. With either color scheme choose a basic floor tile with a bit of texture to prevent falls. A rectified porcelain with touches both cool grey and warm whites and taupes would work with lots color schemes. Keep in mind you may change your style in a few years. So pick a classic with lots of options. It will be easier to change a dramatic paint color than a busy tile pattern.