Is that a sliding door between the bath and bedroom?

If so, id do without it.

How is the 24” shelf accessed and what is it for?

How much space is there between the sink and the shower? that doesnt look like enough for a walk way

I think you'd have to have a sliding or pocket door, or it would conflict with the entry door into the bedroom. I assume the space to the right of the plan area is another bedroom with direct access to the bathroom, and that's why you're calling this a jack-and-jill bathroom. Do you have to go through that bedroom to access the new bedroom, or is there another way in?

@Indecisiveness, thanks for chiming in.

1) The shelf would have to be accessed by going where the toilet meets the wall. Shelf is 24"x24" square, and could store towels/linens.

2) Right now there is 20" between the shower and vanity. I could make it 24" by using a smaller vanity (24"), and cutting the closet down to 48"x24".

To get more than 24", I could get one of these 24" corner vanities.

@artemis78, the space on the right is the living/kitchen/dining area. It is a 700sqft 1/1 granny flat.

Yes, It is 2 doors and a pocket door hidden behind to convert the space as a master when needed.

It feels too tiny to me…and it is not clear how it is to be used…i was thinking along the lines of pushing a long closet out at the end of the bed …into the adjoining room and moving the washer into that room also…the bathroom will never be big enough for a master…and addressing the whole space may offer an even better layout …with more versatility

Not sure where you live, but even 24” between the vanity and shower is not enough.

Can you move the bedroom wall 10”, to make the bedroom 11’ 0” and the bathroom 7’6”.

Also, id look at reducing the shower from 42”x42” to 42”x36” or even 36” x 36”.

What is your plan for this space? for an aging parent or as rental income?

Do you ever envision "granny" being on a walker or in a wheelchair? You must take those possibilities into consideration. Look into the principles of ADA compliance for your flat before you go ahead with this. A wheelchair needs 60" for turn around space!

Given that it's not actually a jack-and-jill then I'd just pick one of the two door options and ditch the other. (I'd choose the one opening to the bedroom, but either works.) Agreed that 24" isn't enough space between the shower and vanity even if it's technically to code--we will have 30" and even that feels tight. And would definitely try to get the laundry out of there if this is part of a larger living space. Depending on what's happening on the other side of the wall on the right, you might be able to open the laundry space up to that room in a closet, or otherwise place it somewhere that's not right next to the toilet. It would probably help to see the whole floor plan (and maybe what is there now, too).

If you have plumbing in the wall behind the sink - the pocket door won't work anyway...

And yes - depending on the occupants of the flat - (and maybe even not) the bathroom simply needs more room. I'd prefer it without the laundry too.

700sq ft SHOULD five you enough for a decent layout.

Is it for a granny, a real granny, a potential granny, or some other purpose?

I like @lmckuin's reconfiguration. The sink would be in an alcove between the back of the washer/dryer closet and the bedroom closet. Adjust the width of the bedroom closet to be sure the washer/dryer closet is deep enough to accommodate the appliances (you'll have to decide whether you want it to accommodate full-size appliances or compact models). Slide the toilet towards the door to allow for a deeper shower.