The attached photos depict how the 3-piece bathroom rough-in located in our basement was installed by the builder.
The 2-inch PVC by the wall is assumed to be for the sink.
The 4-inch PVC (reduced to 3-inch) is assumed to be for the toilet.
The 2-inch PVC (with trap) is assumed to be for the shower (or tub).
The 4-inch PVC below the 3-piece rough is footer drainage.
I have also attached photos of what I believe is a 1 1/2-inch vent line that was extended into the basement from the first floor (by the builder as well) and am wondering if I am allowed to connect my basement bathroom vent(s) to this line.
As I have been read conflicting information online, can someone please tell me how all 3 of these pieces are plumbed and vented properly.
If there are further questions or additional information is needed, please ask.
Thank you in advance for the help!