Re: Some Lilypond questions.

[John Sankey]

"4) Some expression marks or comments do not need to be aligned
    to a single note but can or should span many notes, for example
   crescendo is sometimes indicated with "cresc." spanning the
   first notes."

set Voice.textEmptyDimension=1
and put ^"cresc." after the first note to be spanned.

Sorry, can't answer any of your other questions.