Okay, so picture this with me here... (sorry for the poor diagram)

I'm putting in a bathroom in my basement. The waste stack comes into the floor right next to the exterior wall.
#1) I'm going to put my toilet next to that. I can just join that to the main waste with a "Y" right? No vent needed?
#2) The main waste line goes across the floor past the toilet at such an angle that the sink I'm going to put in will be directly over the main waste line. I put in a "Y" vertically with a 45 degree elbow up the future wall to the sink, right? I will also have to find a way of venting this sink with the vent for the 1st floor bathroom which is above, right? (would I be better bypassing the 1st floor bathroom and tying into the 2nd floor bathroom? The walls in my 45 year old house are like 1" thick mortar/stucko/concrete! Don't want to start digging through those.)
#3) The stall shower at the end I was going to " thick mortar/stucko/concrete! Don't want to start digging through those.)
#3) The stall shower at the end I was going to " into the rest of the main waste line before I tie right back into the rest of the existing line. Am I forced to vent this shower stall or will that whole "WET VENT" into the rest of the main waste line before I tie right back into the rest of the existing line. Am I forced to vent this shower stall or will that whole "air admittance valve" thing (See This (http://www.studor.com/index.htm)) on the sink I'm putting in instead of venting up or not?

Guys, I really appreciate all of your help and infinite knowledge.

... Here is a CAD layout (http://home.wwdb.org/murley/basement.jpg) of what I'm doing.

Here is some video (http://home.wwdb.org/murley/bathroom.avi) of where things are located and what I have to work with.

Thanks sooo much guys for all of your help.

Again, can I "wet vent" the shower stall with what I'm doing and can I use PVC where I'm taking out the CI?

... really crappy.

Here (http://home.wwdb.org/murley/bathroom.avi) is a better one.

... even though the shower will be wet vented, should I put a "T" in the drian pipe of the shower up the wall to an aav to make sure there is enough air to that drain?