Problems when using piano centered lyrics

[Hallstein Lunde]

>  <--- Else I'm rejected because of top-posting

I'm having two problems with this.
1. When using lyrics and repeat volta , the repeating 'dots' turn up in
the lyrics line and the repeat line breaks at the same heights where the
dots appear.
2. I'm not sure whether lyrics should be allowed to collide with double
barlines. It seems to me that the lyrics should have made lilypond
loosen up the horizontal spacing a bit more than it actually does.

\version "2.8.3"
\score {
 \context GrandStaff <<

   \context Staff = "upper" {
       \context Voice = "singer" \relative c'{ f e d c \repeat volta 2
{c4 d e f}}
   }
   \new Lyrics \lyricsto "singer" \lyricmode { Oo oo oo oo Yeah, ba --
by -- doll! }
   \context Staff = "lower" <<
     \clef bass
     \relative c {g4 g a b c g c g}
   >>
 >>
  \layout {
      ragged-right = ##t
      pagenumber=no
   \context {
     \GrandStaff
     \accepts "Lyrics"
   }
   \context {
     %\Lyrics
     \Lyrics
     \consists "Bar_engraver"
   }
 }
}