POO only stinks when you are exposed to it
Chemicals just make poo smell like chemicals
Vapor barriers stop poo smells from getting inside RV just like they do at house
When/if you smell poo then either you have been exposed to poo OR the vapor barriers are broke.
ID/Fix broken vapor barriers and stop exposing yourself to poo....No stink!
Simple.
As for dried out poo going back into solution....MAYBE
But just like that dried dog poo on your shoe water and mechanical friction needed. Sloshing water is not going to do that.
Best to not let it dry out in the first place.
Again...Simple
RVng is NOT complicated. Don't make it so