Basement Rough In

(Please view pictures)
Hello, I am in the process of finishing the basement of my new home that has a roughed-in bathroom drain fixtures going to an ejector pit. I know the large pvc pipe is for the toilet and the square box I assume is for the shower so that leaves the other pipe for the sink…right?

The problem I am having is how are all these fixtures suppose to fit in? It seems the pipes are too close together, or am I just looking at them wrong. I am trying to frame the bathroom out but I don’t understand which way the toilet, sink and shower will be positioned.


Also does my sink require a vent or can I just vent the ejector pit? Any help will be appreciated.

Thanks,
Ken

Below are some of the pictures during construction...

drains

I do not know who inspected and approved that installation, but it would never pass here. The small pipe is the vent for everything, and apparently the sink was planned to drain into it using a tee and then an "arm" to the sink location.