None of it sounds code compliant. 18” sink still requires 30” of width. The shower will probably work ok since there is space above bench level.

Thanks for the input. I should have clarified the space for the toilet and sink is larger so should easily be code compliant (the sink itself will only be about 18” but the space around it is much larger). I am simply trying to decide if the space near the bulk head could be utilized as a shower or if its better off as a closet or something. I only added the sink size to reiterate that this whole space is small and not some big elaborate bathroom layout.

Can an adult stand in the space to shower and lift their hands to their head without elbows banging the wall? If not, too small.

Five feet two inch me would have no problem but I can think of larger folks who would have wounded elbows.

Not even code compliant. Only small kids could use it.