Is the 3" cleanout with 2" pipe out of the top a cleanout and a vent for the toilet? That can change things.
You need a cleanout on a kitchen sink line. You need a cleanout every 135 degrees of change. That would be a 45 and a 90 bend.
You can't do two 90's without a cleanout.
A double fixture fitting is used for two back to back fixtures. However in your case here, I would add the vent where the arrow is.