Questions about papers

PLAGIARISM AND DOUBLE PUBLICATION

  I am writing a paper which will also be a chapter of my thesis.
  Does this constitute double publication?

  In what ways should a student be careful about protecting their ideas and work
  in progress?
  Can you register your idea or your paper somewhere, before it is ready to go?
  Can ArXiv be used for this purpose?
  How are priority disputes resolved?  Is it basically whoever published first?

  I have a detailed proof, and am writing two papers, both of which need
  to refer to portions of the proof.  Can both papers contain the same
  text of the proof?  Or must one paper cite the other?  If so, how can
  I be sure paper A will be published, so that paper B can cite it?

  To what extent do journals care about, and check for, self plagiarism?

  The plagiarism policies of journals seem vague about the issue of
  paraphrasing.  Do they really mean that I can't take a paragraph from
  someone else and reword it for use in my paper?

  Do journals wait for accusations of plagiarism, or do they check
  papers when they come in?  Do they use software for this task?

FIGURES AND TABLES AND PROGRAM CODE AND SOFTWARE

  If I don't actually create a figure, do I have to credit the author?
  Are there limits on the number of figures?
  Can color figures be submitted?
  Should some material be moved to an appendix?  
  Is there a way to make supplementary material available (programs, data files)
  which might not be worth publishing?
  If I use a specific piece of software (FENICS, FreeFEM++, COMSOL) should
  I state this and include a citation of some kind?

THE VALUE OF PAPERS

  Bill Layton jokes that "for a graduate student, every paper is worth $10,000."
  What is the value of a paper?

  Candidates for a job can be ranked by:
    total number of publications P,
    total number of citations C,
    average number of citations per paper CPP,
    the "Hirsch-index" H,
    Google Scholar's "at least 10 citations" index i10.
  What are these intended to measure?  Which are most important?

  I have two papers, one as a single author, and one as a multiple author.
  How important is it to have single author papers?  

  Person A publishes 5 papers with person B.  
  Person C publishes 1 paper each with D, E, F, G, and H. 
  How are A and C judged?

REFEREES

  How are referees chosen?
  Why do they agree to do the work?
  Are they experts in the topic?
  What kind of response do they give?
  What is the typical wait for a response?
  What happens if you disagree with the referee?
  If my paper is rejected, what are my alternatives?

MISCELLANEOUS

  How do I find out whether my idea or topic is new enough to publish?

  Should the beginning of my paper include a look at previous work,
  even if I will not explicitly refer to that work later?

  How can I choose which journal to submit my paper to?

  What does the "impact factor" of a journal mean?

  Does a journal advertise the typical interval between submission and publication?

  Does a journal advertise its rejection rate?

  How do you figure whether your paper is too many pages or not?

  Suppose I have written up an idea worth communicating, but it's
  not publishable, or it was rejected, or it's not worth my time to
  try to get it published.  What can I do to make it available?

  Is it important to list papers that are "in preparation", "submitted",
  "accepted", "to appear", as well as those that are published?