Pretty close is not close enough and every measurement needs to be clearly marked . How would you include a closet in a bathroom that would be a very bad idea. Without measurements know way to answer. I love Pax from Ikea for reach in closet when there really is not space for a proper walk in. If you changed the layout of the bedroom that whole wall on the right might be able to be closet . Post the plan to scale with all measurements cleraly marked , post here in a comment in jpeg format .

Is this a single family home or duplex such that you're able to move plumbing and change the windows? The number and placement of windows makes adding more closet space difficult. Do you think the bathroom needs to be larger? What you have now is very efficient, not roomy, but for a lot of people it would be fine. It would not be inexpensive to expand it by just a couple feet since you would have to move all the plumbing on that wall. Is it worth it to you to gain just that much space?

What are your specific goals? (bigger bathroom doesn't really tell us anything). Right now you do have a lot shoehorned into the bathroom - do you use the tub? Do you use both sinks? Eliminating the tub gives you space for a linen closet; changing to a single sink gives you more counter and drawer space at the vanity.

Is there really a window in the reach-in closet?

If you extend the bathroom into the closet space, you can build a new reach-in closet to the right of the existing one. That puts the window in the bathroom, which would be nice.

Of course all this depends on actual dimensions and needs.

Separate shower/tub is such a huge waste of space. Is there a tub in another bathroom? Double sinks--why??? Bathrooms are a private space. It's a very common space saving idea these days to put a walk through cloest into a bathroom or put a closet deep in a bathroom. Who wants soggy clothes? Again bathrooms are a private one person room--having to interupt to get clothes is counter indicated. The value of a walk in closet is greater in peoples WANTS than in reality.