A couple thoughts:
In that hall bath, you might reconsider the door into the toilet/bath area. With that door swing, you'll have to straddle the toilet to shut the door behind yourself when you're in the room, and that's assuming the door will actually clear the toilet. You could reverse the door swing, use a pocket door (may not be enough room), or do away with the room separation. It might feel a little claustrophobic splitting up those rooms, but I can understand that it's nice for multiple kids getting ready in the morning.

In the master bath, I would consider leaving the shower head on the other end where it is currently. One reason is for easy access through the bedroom closet if you ever need to repair the plumbing in wall. I would also consider not centering the entrance to the shower, but moving the entrance south so you're stepping out to the space in front of the toilet instead of running into the side of it. Then the shower bench would move to the north wall.

letseatpaste, thanks for the ideas. The pocket door is a good idea. A barn door style mounted on the inside where the toilet and tub are might work. Maybe something like this?

{{gwi:2133775}}

[Contemporary Bathroom[(https://www.houzz.com/photos/contemporary-bathroom-ideas-phbr1-bp~t_712~s_2103) by Elkhart Doors Johnson Hardware

I did want some kind of separation because we have a son and daughter, so we were trying to improve efficiency with a shared bathroom.

On the shower in the master, that's a good point regarding access to the plumbing. I had not thought about that. You're right about not centering the access, too. We only have 5 feet to work with, and we want to make the shower as accessible as possible. With the shower head in its current location, we have to climb over the toilet to enter the shower. We wanted to improve accessibility.

I don't have any real world experience with either the barn style door or pocket doors. I would go with whichever one feels the most private, least amount of gaps, etc... Nobody wants to see gaps around the door when they're sitting on the toilet and someone else is right on the other side using the sink. I would also pick a loud vent fan, but that's just me. :)

With a pocket door, it's possible to do electric on the wall where the door slides into, but you have to use special shallow electrical boxes and you have to be careful with the wiring, so that's a consideration if you want to put any electrical on that wall. You'll also lose the recessed shelves next to the vanity. Also, if you want an outlet on that wall by the vanity, I would double check and make sure you can get a GFCI outlet that is shallow enough for the pocket door.

With the barn style door, you'll probably want to allow a little extra room on that side of the toilet so your elbows aren't knocking against it.

With either option, you'll really want to work out everything to scale with the door hardware, trim and everything to make sure it all fits on that 5' long wall. Realistically I'm going to guess you'll end up with a 2'-0" door opening there, maybe 2'-4", which is fine unless you want it handicap accessible.

Brilliant annexation of the hallways into more usable space!

The likely reason for the original layout to have had the master shower head on the opposite wall was that back-to-back shower valves would impinge on each others' space running up the wall. You either have to make one substantially off-center in that shared wall or move one to the opposite wall.

weedyacres, is it feasible to make that part of the wall a little thicker to get the shower plumbing on the same wall? Having the shower head moved is important to us so that we won't have to climb over the toilet to get into the shower.

Sure. Just put another row of 2x4s on the end of the shower for a double wall, shrinking your shower by 4", and run your master shower plumbing up the 2nd wall. It would make a soffit-type end wall, but you could tile the stair-step on the outside.