Basement Rough-In Full Bath Questions

[pingman3]

I have attached four pictures of what I have; I don't have a great understanding of vents, etc. Trying to determine what each pipe is going to serve; after removing the cover in the concrete, I was hoping to find a stub, J Trap, etc ready for a shower/bath. Just a 3 to 4 inch pipe running parallel with floor. I am assuming that hole in the conrete is where the drain should be for a shower; does this lay out appear to serve for a shower or tub? Does it matter? Another question is that the middle 2inch pipe is 18 inches or so away from the wall.....? All three vertical 2 inch pipes come join together up top as shown in picture, assuming to a roof vent. Any insights would be greatly appreciated.
Ryan

 

[lordofthepipes]

looks like its roughed for a right hand tub, toilet, and a lav sink. sometimes the room is wider than 5 feet so at the back of the tub there would be a void space that will have to b framed out to create a 5 foot enclosure for the tub. this may b why the vent is so far from the wall, it may be in the void space. i hope this makes sense to you. im not sure what is going on with the 2in pipe in the bath tub cut out. looks like its a wye and a 90. should just b a 1.5in stub.