new bathroom tie in

I would like to put a full bathroom in my basemnt. toilet-sink-shower. there are two white caps flush with the slab floor. ( 4in ). I believe one or both are the drain rough in. they are about six in. apart on centre. the one closest to the vertical drain is a tee. some how connected to the stack drain for the laundry. the other one has cold air rising from it when the cap is removed ( it appears to be a 90deg elbow of some sort. Both seem to be too close to wall for a toilet. so i think i wil be busting some concrete. any suggestions on how to connect all my plumbing ( drain ) needs. what is the second rough in for?

Where is your main stack and main drain line? How far is the bathroom from this stack and/or the main drain line?
The toilet needs at least a 3" line within 5' of the stack with the flange 12" on center from the finished wall behind it, a 2" vented-after-the-trap drain line for a shower, and a 1.5" drain line vented-after-the-trap for a sink. All drain lines need to be sloped 1/4" per linear foot toward the main drain. Vent pipes need to be tied into the stack. The toilet has a built-in trap, the trap for the shower should be directly under the shower drain, and the trap for the sink under the sink.
Don't know what those caps are on.
You first need to contact your Building Inspection Department for local codes, permit and inspections requirements, which you'll need anyway.
You can rent a concrete cutter or small jackhammer to break up the basement slab.
Good luck!
Mike
(NOT a pro plumber)