\version "2.13.57"
\header {
  texidoc = "How can I increase the spacing between the footnote and the tagline or copyright markup?"
  copyright = "© by No One. All right reserved, even though no rights exist..." 
}
\paper {
    footnote-separator-markup = \markup { \fill-line { \override #`(span-factor . 1/4) { \draw-hline } \null }}
% None of these spacing settings work to separate the footnote from the footer:
	last-bottom-spacing #'minimum-distance = #10
	last-bottom-spacing #'padding = #5
	markup-markup-spacing #'padding = #5
}

\score {
  \new Staff \with { instrumentName = "Organo *" } 
    \relative c' {  \footnoteGrob #'NoteHead #'(0 . 0) "" "* Realization of figured bass: Reinhold Kainhofer" c1 }
}