my 2 bobs worth. as someone who works with the elderly-the en-suite for your MIL is still not right. if she ever needs walking assistance,especially with a frame, getting past that door into the en-suite will be a nightmare. swap the vanity position for the shower. ensure there is no step-down into the shower area, and ditch the shower screen for a curtain. will make access much easier. especially if she ever needs assistance showering..it will be virtually impossible, and dangerous, with your current design. thinking long term..MIL will not always be there with you, so presumably you and your hubby will at some point end up in the master bedroom? consider the long terms implications of this-no good building something that suits her now, but would need major modification to suit your needs later. I would actually do away with the WIR at this time. Plan to add it later, if you would want it for yourself, but i would just use free standing furniture for her-no doubt she probably has her own, so it would be nice to have some of her own furnishings when she moves in with you - to make it feel more like her home. it will free up some floor space, and make access to the ensuite easier, without having to turn corners. I would also do away with the extended passage into the master. Take that door back in line with the other bedroom. Currently, it adds nothing, and may well limit your furniture placement for your family room, as the walkway will need to go around it. i have issue with the 2 person shower and double vanity in the same room. s the kids get older, they /you probably wont be comfortable using the room when you are showering, so mornings will be slowed down. Have you considered a 3 way bathroom/toilet/vanity area? We had this in our house, and it was the best decision ever. The shower and bath were in one room, with a separate toilet, and then a double vanity which opened to the passage. Everyone could use everything at the same time, without encroaching on each others privacy. Not sure about your state -but here, the toilet door would have to open out-if someone collapses in the powder room, you would not be able to get in with the door opening in, as they would be blocking the door. I do empathize with your dilemmas. We have spent 7 years planning an extension and remodel, then 2 years (!!!) working on the design with an architect, going backwards and forwards, and then the last 12 months nearly, changing and fine-tuning along the way as things were being built. It is not easy, but worth it. Having said that, you are unlikely to ever get it perfect, as your needs will change, your likes/dislikes will vary, and you will see other peoples homes and go "why didn't we do that". (Now if only i could take that on board myself, LOL)

How's it going ? U in yet? You loving the country life? Great flower stalls on that road, or use to be! $2 bunches.. Can you look at my 'tiny house' the size of your powder room..lol https://www.houzz.com.au/discussions/6042198/those-with-an-eye-for-colour If you have any other ideas. I got some good ones already. But throw any more around that you think might work.

custom made vanity and wall cabinets should only be needed if you have awkward sizes as an off the shelf cabinet allows you to see and touch the product and is often much more economical than custom made ...unless you need to keep some special supplies (eg 24 pack of toilet rolls?) i suggest that a base cabinet need only be 450-500 deep which is plenty for folded towels and drawers and the in wall cabinet about 150mm deep (including most of the cabinet inside the wall and only a small frame for doors and mirrors projecting out) but the in wall cabinet may depend on existing wall studs and electrical wiring so think about what you would put inside the cabinets and only have enough inside cabinet space for those items (maximum toilet roll or fat shampoo bottle about 120mm...in small bathrooms the extra floor space makes drying and dresssing much more comfortable and by rotating the shower in the family bathroom there would be less wet floor in the walkway and if the vanity in the ensuite is away from the corner you can allow space for a handtowel and/or a very convenient space to hang a hair dryer ...

En-suite layout is fine, Looks like you have a double hung window with a slightly lower sill to the vanity height. . I’d put a stool in front next to shower screen. Update vanity and top and splash back, maybe lowering mirror. Could put a niche in the side wall if want extra storage. Could change mirror to a cabinet, even if it protrudes, mine does, A smaller basin would increase spaciousness and bench space. Can also increase depth of vanity, to 550. Replace floor tiles if you want but I’d leave shower if you want to keep costs down. otherwise retile to full wall height will improve look. Could add a pendant light over left side of vanity