Well the 3DPT boards are a little different than the diagram. Like I said the ins and outs are switched. Is the connection between J! and JO via the green lead necessary?
I would think so. Think of it in terms of 3 circuits, not one. If you had 3 PCVs, then the JO of the first daughter board goes into the JI of the next.
It's not the cleanest execution but should work fine. Might be a good candidate for shielded wiring with the small bowl of spaghetti that it will result in. At least theirs convenient ground pads on the daughter boards.