No tees on back can receive any drainage. You need to vent that toilet some how? Is the three by 2 tee on its back the lav for the bath room?
I would suggest you install a 3 by 1.5 inch wye run to the lav and use an AAV vent if approved by your local plumbing authority on the lav above the p trap picking up the drain.
I would suggest you install a 3 by 1.5 inch wye run to the lav and use an AAV vent if approved by your local plumbing authority on the lav above the p trap picking up the drain.