drain
Let's simplify it even more. First run the 3" drain to the lavatory/sink location. Put it low enough, about 19" below the concrete so you can install a long radius elbow for the turn up. Then place a 3x3x3x2" left hand side inlet tee pointed towards the toilet's location. Use a 2" street 45, 90, or whatever is necessary, to run from the 2" side inlet to the tub. Put a 3x2 bushing in the top of the tee, (if your area does not require a cleanout at the toilet), and then run up to the sink tee. You will eliminate a lot of fittings and frustration.