In the drawing, I put the 3" line over so the drawing of the toilet wouldn't block it for learning purposes.
In the real world, I would have used a wye and street 45 and kept it within the 14.5" stud space behind the toilet.
In some cities here, we can wet vent the lav into the 2" wc vent, but not all cities.
Inspectors like to get their respect, sometimes by having their own interpretations of the codes.
One year I was plumbing in meat markets into food stores in ten cities.
After meeting with each inspector, I ran the plumbing ten different ways.
Every inspector thought he was the smartest in the state.
A little confusing though, running them that many different ways.
In Tacoma, one gold necklaced, open shirt to the chest inspector informed me that they didn't like outsiders doing "their" work.
I asked for the first inspector I had talked to and the inspection was completed.
I've always wondered if he was hinting for a bribe or if he was just goofy.
I remembered that my father used to tell me stories of Tacoma years ago, he was a district court judge in King county, and Pierce county used to bring him down there if they were "trying" one of their judges.
I hope things are better now there.
Anyway, it doesn't hurt to talk to your inspector before you get too carried away thinking you can just go by the code book.