Were any of these tactics used, to cover-up, on software projects ?

You said covering up on software projects - some of this looks like covering up for a crime. I'm a computer programmer (currently unemployed). I don't think I really ever tried to cover up anything, I found it better to be honest if I made a mistake and work on fixing the problem. Everyone is human and clients tend to be more understanding when you admit your mistakes and know you are trying to fix it - when you lie and make up phony excuses they usually know it, and then they can't trust you. The only "cover up" would be if I was asked why something was taking so long. It is easier to do this if you work on different projects for different people, you can say that some other project was more involved than expected and you didn't have as much time to work on their project. Or you can say that their project was more complicated than expected, more things were added to the project, etc.