To a homeowner, I'm sure that the waste and vents are overkill. Until you have to start using them.
You can't run a bathroom group past the shower without venting between the wye and the trap to prevent siphoning.
The Santee can be used vertically, but that gets trumped by the bathroom group running into it.
The suggestion above, putting a wye on the stack, bringing it up to a 2.0 x 1.5 x 2.0 santee and having vent for the shower makes the most sense.
I have no idea what the 3x2 lo-heel would be venting, if the bathroom group is already vented.
http://terrylove.com/images/dwv_b2.jpg