That is what those are. I do construction.
The square box is framed out there won't be any concrete there once he takes off the tape. Find a 2"pvc pipe sticking up. That is where the shower drain will go. The ring on the floor, that is a toilet ring. Not getting away from that one. The way it is currently oriented the toilet can only go one of 2 ways. 90° opposite of the slides. The other two coming up, the #1 is too close to the shower to be the sink, it is also too small. That leaves it the vent. The last one sticking up, that one is far enough away to allow for a vanity. Thus a sink.