The answer(s) to your questions and situations, will depend largely on the environment that you're in. For example, public accounting has a multilayered protocol based on the types of client's - those business types, who is on staff that has experience with the particulars in that business, and what kind of ownership is involved. Family business, partnerships, closely-held, and so forth are mainly concerned with a set of priorities that are far different than other types of enterprises, the same size, but of different ownerships.
The corporate environment is dictated by the corporate structure and the diversity of the industry, staffing, business model, and a ton of other disciplines. Each and every corporation is unique and structured like no other. Hence, two stages of auditing usually the case, as appose to the auditing format by the small size CPA firm that primarily deals with the local business population. The first stage can be the internal auditing procedures, and then the public CPA firm that follows.
So, with fact-finding your questions, you'll have to focus on the business model first, then approach the size of the audit structure that
serves that/those modes, then on top of all that, the specific industry within that model. My last example can involve a complex set of
criteria's, over and above financial and simple GAAP. Take for example the firearm's industry. A ton of business, Federal compliance and other need-to-know particulars that are all in orbit at the same time.
I hope this gives you some direction and doesn't confuse your search.