In case it is of help to you - Our concealed laundry dimensions are 2406mm X 700m deep with two bifold doors concealing this span. The bifolds have this mechanism https://www.hettich.com/au_EN/products/folding-and-sliding-door-systems/folding-door-system.html and it is very smooth. The large sink, washer, dryer fit into/under a bench 1875mm long and the extra space is the broom space. The entire length has overhead shelves. Two things I like about ours are the location and proximity to the outside clothesline and the natural light and unrestricted space around the cupboard. I wouldn't find it as nice to use if I only had a narrow space to manoeuvre. You will also need to consider ventilation for the dryer (if you haven't already).

just as well you challenged the sizes of the rooms as the spaces shown will make a very generous guest bathroom but not enough room to walk through the laundry as the floorplan doesn't seem to be drawn to scale so I've made two plans with actual sizes available for comparison... by reducing the width of the guest bathroom and increasing the laundry there'll still be enough space for a supersized shower and twin vanities but there'll be enough room in the laundry for standard storage cabinets, space to open the sliding door and also open the swinging door inwards, so as not to block access to the stairs, and just enough space to use a standard sized ironing board.. The small hallway is a bonus adding extra privacy and sound screening and solid core doors will improve this even more and then choice of fixtures and fittings will make a good choice even better

disappointing that your landlord is not more responsible and more difficult if you're at work and your partner is not well: if there's no legal agreement about who owns what and you've been told to "deal with it" disposing of anything that you can't use or is not obviously valuable...it's not safe to raise the washing machine without a specialised washing machine stand and it will be more comfortable left on the floor to use the top of the machine as work space... try the simplest cheapest options and keep only the essentials on a shallow lower shelf and hopefully the top shelf may have room for some of the culled boxes from the bedroom...check out the various shelf options in the on line Bunnings etc catalogues ..unfortunately the paint can't go in the bin so make sure the lid is secure and with the help of some hefty friends carefully enclose the paint can in plastic garbage bags (in case of spills), load it in the boot of the car (supported by something to keep it upright) and take it to the nearest recycling garbage tip...hopefully the worst that will happen is the owner will need it replaced if/when she wants to do more painting.. if you need an oven it could be worth finding out the cost of a repair but it could also be no more costly to consider buying your own convection microwave and use the old cleaned out unworking oven for storage of some of the stuff out of those boxes...for the rotting kitchen bench there's a product called "builders bog" that can fill in all sorts of horrible problems and then (carefully covering all the other surfaces use a cheap can of (red?) spray paint to at least make the bench look a bit better and, one box at a time you can take control of the situation, best of luck to you

If the rumpus is going to be used as a family day care room, then I think the powder room should be accessible from there. This will make it so much easier for one person to supervise the kids in the room as well as the one who is heading off to the toilet. Perhaps you also need a wet area in there for cleaing up after messy activities. I know someone with a similar family day care set up, and they have toilet and laundry attached to the back of the garage/daycare space. And then the kitchen is adjacent, this makes life a lot easier for the sole person in charge of the kids.