Cast Iron Pipe Replacement - Looking for feedback on my current plan.
A family member recently bought a house, and I am helping them repair their 2nd floor bathroom. When I removed the subfloor, I found the vent had completely broken off from severe corrosion. Other sections of the cast iron had been spot repaired over the years, and I have decided that it is time to completely replace all of it with PVC.
The last two pictures are drawings I made showing my current plan. The bathroom is small, and the toilet needs to go back where it currently is. I don't think I can replicate the cast iron exactly as it is with PVC. Due to space constraints, I am planning on using a wye on the stack to branch off a 2" line to the sink and tub/shower.
I want to make sure what I am proposing is going to work correctly and not cause problems. Am I overthinking the vent connection by tying it into both the 3" and 2"? I am looking for feedback to see if there is a better way for me to fix this.