New bathroom remodel advice

[JSPA]

I am working on remodeling 2 back-to-back bathrooms in a 1950's home. I put together the attached drawing and wanted to run it past the pros here before final plumbing so I get it right the first time.

A couple notes not on drawing:
1. Plan is to cut old copper 3" horizontal before first toilet connection and convert to PVC with Fernco.
2. The vent is the only one on house (2.5 bathrooms and typical stuff like laundry/kitchen/etc)

I have been using this forum for years and really appreciate the great discussion and assistance given. First time posting so if more info is needed I can try to supply. Thanks.

 

[Terry]

Two or more lavs will need 2"
They make a shielded coupling for copper to PVC. That's the one with a metal wrap to prevent the pipes from shifting, which does happen with an all rubber coupling.
Your tub and shower are not vented correctly. I can't tell if the lavs are either from the drawing.

 

[Sponsor]

 

[JSPA]

What additional info would be needed to determine Lav venting? I was not planning any changes on the tub/shower fixtures because their connection to the main is not visible, so I have no way to determine what their connections look like. For what it's worth, I have never had flow issues with those two fixtures.

 

[JSPA]

So I revamped my layout a bit based on your feedback and other posts about double vanities. I also picked up the copper to PVC shielded coupling you mentioned. Thanks.

 

[hj]

I do not know what "2 way T Y" is, since I have never seen one. Your tub, shower, and right hand toilets are not vented.

 

[JSPA]

The picture below is what I was going for on the double tee-wye (sorry, unsure of exact name for fitting). The left sink would then tie in to the vertical below that double fitting.

What makes the right hand toilets/tub/shower not considered "wet-vented" from the 3" drain line? I was basing the layout on the attached from a book put out by the International Code Council about venting procedures. Any suggestions on what I am missing?