The mess of information coming through the various channels, some controlled and some uncontrolled, I believe is actually a good defence.
The company has lost control of the flow of data. So many manuals have duplicated, contradictory data. So many channels are uncontrolled. The authenticity of the information is often at question. Much is not part of the legal documentation so can be ignored.
I think if if got to a legal scrap after some kind of omission resulting in action against a crew, a good lawyer would have much to work with. Some serious questions would be asked higher up and embarrassment and dismissal of those responsible would probably result from the legal argument.
Stick to the basic SOP, forget the rest. Its impossible to keep up. Take out some good legal insurance. Write the odd email about the overload of information and changes, and keep it on record.
If ever anyone throws the book at you sling it right back.