I just can't see how this meets any type of code. The toilet seals itself when not in use, a shower drain trap can dry out and let the oders and gasses into the RV, that is not safe. I tried looking to see if there were any RVIA codes on this but really didn't get very far. Below is what I found in a quick look, when I tried to find the NFPA 1192 all I got was a pay link for $52.
Plumbing Systems as specified in NFPA 1192 Standard for RVs.
* Only listed plumbing devices, fixtures and appliances that have been labeled by nationally recognized testing agencies are allowed.
* Water distribution systems are sized to provide adequate flow rate and designed to prevent backflow contamination.
* Fixtures with traps and vents must be provided to protect against siphonage and back pressure.
* Vents to release gases from any waste holding tank must be provided.