Drains and vents for bathroom and kitchen

[Whale]

I am adding a bathroom and a kitchen in a renovated attic space. Please let me know if this drain and vent design will work. Also where the kitchen sink hooks into the 3 inch stack in the wall I want to use a 3x3x2 sanitary T and a 2 inch street 90 because there is not much room in the wall. Should I be using a Y instead?