Need quick advice on 3 floor bathroom layout

I have attached a sketch of what I intend to do to add a bath to a thrid floor attic. A 1/2 bath was roughed in but I wanted to change the horizontal drain to accomodate a shower. I can only add a seperate vent to the shower upstream of the shower p-trap is this OK? I may not even need one given that its also vented (wet) via a kitchenette sink I will also add. This is vented through a seprate stack.

See sketch for details. NOTE: RED lines indicate vertical runs

Thanks in advance.
Joe

Please note that the 1 1/2" vent upstream of the shower runs parallel with the 2" drain before turning up (30" run) to go vertical through the roof on a seperate vent

A kitchen can't wet vent any bathroom fixtures.
Wet venting is only for a bathroom group on the same floor.

If you have a sink above, the waste for that will have to come in lower or downstream of the shower.

Thats what I thought you'd say. I can tie into the drain down stream of the shower with a little work. How abour the vent thats near the shower wye? is that OK?

The vent for the shower should come off the trap arm, not the stack.

IF you leave the stack the way it is, and reroute the sink connection below the shower, with its own vent, then you do NOT need that separate vent.