I don't think a blog post can possibly cover all the cases. A book will get you closer. For a great book on exactly that sort of subject matter, I couldn't agre

I don't think a blog post can possibly cover all the cases. A book will get you closer. For a great book on exactly that sort of subject matter, I couldn't agree more with the author of TFA: Working Effectively with Legacy Code is a book that everyone should read at least once. It's been a while since I personally last read it, but, as I recall, it has an entire chapter devoted to each of your examples.