As a side note to your nice explanation: You are free to choose the ordering of code and data (encoding). If you start from code+data (opposed to data+code), you'll get a functional programming style quine, like this:

sub{print qq[sub{print qq[$_[0]]}->(q[$_[0]])]}->(q[sub{print qq[$_[0]
+]}->(q[$_[0]])])
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In a digestible form (but this way it screws up the whitespaces):

sub {
  print qq[
    sub {
      print qq[
        $_[0]
      ]
    }->(
      q[
        $_[0]
      ]
    )
  ]
}->(
  q[
    sub {
      print qq[
        $_[0]
      ]
    }->(
      q[
        $_[0]
      ]
    )
  ]
)
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Sorry for the parentheses haters.