Hi. Try moving master door to opposite bed 3. Then move linen into the old master doorway and square up ensuite. Old linen becomes a vanity for toilet. Keep it outside toilet. Good luck

will the upstairs only be for the master suite or do you still need to have access upstairs for a separate bathroom and bedroom for others...what about something like this?

another option with access to the family bathroom for all upstairs bedrooms and a new linen cabinet allows extra storage for the other bedroom

please confirm that you need both bathrooms to be made bigger and are prepared to completely demolish both existing bathrooms to create two new bathrooms......???

trying to work around the existing windows and savings as much of the existing plumbing and walls as possible..what about this option??

my concern with the windows was to make sure that there is a window for light and ventilation for each separate space but it should be quite simple to build shelves to suit the windows in the wiw but what is the size of the windows in each room? that is width, height and distance above the floor?

there's almost twice the storage area than in the old wiw without counting the space around the windows

Can u swap study and main bath. Give window to study add skylight to bath

I like the suggestions from oklouise, those could work. however, when I had to remodel my upstairs rooms I relied on these Melbourne architects and they did a great job with rearrangement and remodel. Hope this helps and good luck with your remodelling! :)