bathroom vent

Good morning, gentleman. Found some termite damage, and a leaky shower curb and one thing lead to another and I’m now remodeling the 1st floor guest bathroom and laundry room on my tri-level home built in 1976-ish. I figured since I had the bathroom walls were opened up I would move my...

I'm replumbing an existing basement bathroom that doesn't have vents. Does this diagram look right? 1. Can I add a shower vent to the end of the 3" main horizontal waste line just beyond where the 2" shower line meets it? Is this to code? 2. If the sink is vented, do I even need to add a...