You'll get a lot of speculation from people based on their experience and preferences. But did any of the people who said you would be cold ask where you lived? Maybe you are in Bora Bora or maybe you are in the Arctic. Maybe your house is drafty and maybe it's tight and you keep it at 75 degrees. Free advice is worth what you pay for it right? We have a doorless shower and it is not cold or drafty. The house is new, well insulated and has warm floors. Also the bathroom itself is not large. The splashing is minimal and we put a tub mat at the entry to the shower to step out on anyway so we don't get the rest of the floor wet. All of that or none of that may apply to you. (But I did see some great advice here that I took, which is to have the controls at the door and opposite the shower head.)

By IRC, the ceiling height may be reduced to 60" "where people cannot walk" which means the back of the sink or the back of the toilet, or a shower area taken up by a bench (as long as the 30" hoop/80"is met in the shower) , so right now it appears that the toilet is in a spot that would no longer be permitted. You definitely have the room to get a legal powder room in this space (by international code/your local codes my be more stringent), ceiling height and all. Maybe just not with this toilet location or position. If you could move the toilet it may help, but moving a toilet is not cheap. The other thing is since you have a hole in the roof already, you may be able to enlarge it and pop up a dormer. Again, not so cheap. In my location, if the toilet was not relocated and was 12" on center instead of 15" (the old requirement), it would be grandfathered. Actually, that would be allowable in some circumstances now even if the bathroom were completely reconfigured (such as it being the sole bathroom in the house and only having limited room). A toilet in that position may have met a local code at the time it was permitted, or at least passed in your jurisdiction at one time, but currently it could really only be in this general position if it were turned 90 degrees and the Tank was against the knee wall. Could you draw this in a plan and indicate the various ceiling heights throughout?

Okay, just saw your new proposed floor plan... You're trying to fit WAY too much into this room. The new toilet location is problematic in that, according to the IRC, you need at least 15” (again, that’s if I recall correctly) to any obstructions on either side of the centerline of the toilet. In other words, you’d need a MINIMUM of 30” of wall space if you wanted to place the toilet there, and the toilet would need to be centered. And you do not have room for a dual vanity. Even if it technically fits, there‘s just not enough room for two people to comfortably share a 40”-wide space. I get that you want it all (who doesn’t?), but you can’t have it all—at least in a room this size. Sorry! 😕 Btw, the code requirements I’ve included may or may not even apply to your particular set of circumstances (I’m only using them as a reference point), so you’d need to see what, if any, rules apply to your location.

@Julie K - I spent a LOT of time researching my adjustable bed and mattress when it was replaced and I am super happy with my choices. After reading a lot I went with a adjustable bed frame from Legget & Platt. I bought in Fall 2017 and got the Prodigy 2.0 which was then their top of the line model. I would probably get whatever is the top of the line model now because they have added adjustable lumbar support feature as well as the standard head and foot adjustment features. Leggett & Platt Adjustable Beds I also spent a lot of time physically testing mattresses and wound up with a latex mattress - or more accurately a mattress which has the "comfort" layer made of latex with a top layer of merino wool for temperature regulation - or so it says. When I have to replace the mattress I might go with 100% latex but my current mattress is like sleeping on a supportive cloud. FWIW latex is completely unlike memory foam/Temperpedic which I also tried but didn't feel comfortable sinking in as it made it more difficult for me to shift positions - but that is me as friends love their Temperpedic which is why physically testing mattresses is so critical. If anyone is buying a mattress in Los Angeles I really recommend Legacy Mattress on Overland near Venice Boulevard. It is not a chain store and the owner (Joseph) is incredibly helpful and knowledgable. When I walked in and told him what I thought I liked he made a few suggestions and although I test all of them by lying on them I wound up with the one he thought I was going to find the most comfortable - he is kind of like the mattress whisperer. Legacy Mattress