Strange Rough-in. What are our options?

[DaysUntold]

TLDR: Strange rough-in. Need layout for full bath, less than 55' if possible. Ignore tape lines.
Note: there is less than an inch between the sink and shower drain. A wall won't fit between them.

Need help deciphering this rough in layout. It seems a bit counter-intuitive to us and we're having trouble deciding how to place the fixtures in a way that meets code and is functional. I even checked the builder's floor plans for optional finished basements (we didn't work with the builder, but we know who built the house when it was new) and they all had standard vanity, toilet, shower layouts against an outer wall. This is in the middle of the room and in a way that prevents everything from lining up nicely (unless I'm missing something.)

As a side note, it is helpful if the room is able to stay under 55 sqft, as then we won't have to add in another sprinkler. I've attached a taped off version of one of our plans, which includes a privacy wall and door for a standing shower, but that would require a plumber to come an add another sprinkler. I also included the floor plan for the basement remodel and a scaled up version that shows where the pipes are.

 

[DIYorBust]

If there is an intended design here I did not see it. But I think you might be able to save this, and here are two tricks that might help. One is a rear outlet toilet, the other is noticing that you can relocate the sink as long as you can keep that drain in a wall because you have access to vent overhead. I believe generally, a single lav(bathroom sink) can drain on 1.25 pipe, although 1.5" is more commonly used, and either should technically fit in a 2x4 stud wall, but consider using 2x6 walls where there will be plumbing. I think you want to build something like this.

 

[Sponsor]

 

[Reach4]

"all measurements are based off caps on pipes".
What does that mean? Is that based on the nominal size of the cap, or is it measuring the OD of the cap? Nominal 3 inch pipe is 3.5 inch OD. Nominal 4 inch pipe is 4.5 inch OD.

What is the problem with this? Green represents a wall which does not go clear across the room, although you could make the shower a separate room as your original blue taping implied.

Ideally the center of the toilet pipe would be 12 inches from green wall. The lavatory edge would be 15 inches or more from the center of the toilet pipe.

 

[DIYorBust]

I think the problem is that it's unusually large without good reason.