Would you essentially just be getting new fixtures if you kept it as is? They would almost have to grandfather it then: if not it would mean that you couldn't replace a broken toilet in an old house. According to International Building Code, a toilet and a sink can have overlapping clearances, so part of the knee space for a toilet can extend under the sink (9 inches, I think). And if you did 30" on center for the toilet you would have 15" on one side and 15" + 12" on the other, so the sink could be on that side. (However, you may be required to put the toilet 36" on center which would give you 18" on one side and 18" +6" on the other)

I like the larger bathroom, but I think the doors conflict and it is nice to have them open into the closet. I'd do a good pocket door into the bathroom to avoid more conflict although it could open against the wall next to the sink. You do loose more closet storage, but corners aren't all that valuable in a closet. You could fit a lot of clothes in there by double hanging rods. That would save some money over the Pax system. Plus your closet now seems more separate from the bathroom by extending the wall. Here is another idea for the main bath. My daughter has stacked washer and dryer and is short, but uses the arrangement well. You have plenty of room in front of the W/D to get clothes in and out. The toilet is off to the side. The vanity could be 72 inches with 2 sinks. The bonus is the door would open up against the tub and the room would feel more open. The laundry would be easily accessible without the bathroom door being in the way. Folding laundry in the laundry room is overrated. I had a nice space for folding laundry in our 1 st house with a window to look out. I usually took the laundry to the TV area and sat down on the floor to fold.

Do you have an elevation drawing of that stairwell in the living area? Seems the space under the stair landings could be better incorporated in your effort to locate the powder room, or at least the hot water, accessing from the closet by the entry and moving the sloset to the living room side. On another subject, am I mis-reading or are there bi-fold doors by the tub in the main bath? Looks like there are windows in the WIC. I would rather have windows in the bath and walk through the closet to get there than have to walk through the bath to retrieve clothing; not convenient if there is someone using the bath. That pantry at the foot of the stairs looks like a good spot for a stacking WD. I'd want it configured to vent out an exterior wall, using pullout pantries in the kitchen so that space could be the laundry. But first I'd move that big bath's footprint to the deck end of the space so the closet could be in the master.

My option would have separate rooms/sinks. You could also include the 20” behind bathroom for a small closet or built in shelves. The laundry sink would be smaller, but a small drying rack could be installed above the laundry sink or on the wall above it. Does that give you all of the utility/drying/storage you need there? I’d look for a small stainless steel sink with deep capacity. If you need even more space in the laundry area, you could get an even smaller sink on the bathroom side. You need a “to scale” plan on grid paper or digital app to get into the details and figure out sizes and how it will all fit together…like a 3D puzzle.