I think that your idea is good, but a bit vague. Maybe this page in CRAN can serve as what you are looking for in a FAQ for Ubuntu?
Plus, I'm not sure this is the right place for issues with apt. Can you be more specific into what you have in mind? Some packages have dependencies, these should be documented in the package instructions. If they are not clear, maybe ask about these issues with specific packages and what errors/messages you get when you try to install them.
Something else that comes to mind, are you talking about apt complaining about an unsecure repository (or something like that, I don't remember the actual wording)? Maybe you need to add the key for it? Check the example here.