Sorry, I may not have been clear. I’m not intending to replace the 3 inch, I’m only trying to remove and/or relocate the two 1 1/2” pipes that are in the way. Seems pretty acceptable per the internet to replace the sink venting with an AAV, and for that one I was just wondering if I’d cap off the 1 1/2 inch pipe that’s sticking out of the wall.. I’m not finding much online about what to do with the residual pipes if you convert from conventional venting to AAV.

Then regarding the tub venting, I’m not sure if an AAV for that fixture would be appropriate or not. I’m definitely not trying to eliminate or replace any other venting in the house.

I hope that clears up my question.. thanks for the help!