[Ghostmaker]

Please hang on till Eplumber responds he is a plumber in a UPC state. Your venting below the fixtures would not be approved under IPC code but I can't speak for your area.

 

[Ghostmaker]

I figured keeping the vents out of the walls, and instead putting them in an easy-access crawl-space is the better way to go.

If you vent correctly very slim odds you will ever need to snake them.

 

[Ghostmaker]

3 is the only correct posting. Eplumber we ain't so far apart on code. That island vent is only legal in IPC areas not UPC but the picture forget the required clean out on the flat vent.