Global fonts

[Jakob Pedersen]

    Hello!
    
    I'm trying to change the fonts of my scores. It's a \book consisting
    of several bookparts with a single \paper block.
    
    I've sent a new roman font using this in the \paper block:
    
      #(define fonts
          (set-global-fonts
           #:roman "Libertinus Serif"
           #:factor (/ staff-height pt 18)
          ))
    
    I have two questions that I couldn't find an answer to in the
    documentation.
    
    1) How do I apply openfont features globally and not in individual
    markup blocks?
    
    2) How do I make a global change of the font used for lyrics? I
    assumed it would change with the roman font, but they didn't.
    
    Thank you.
    
    
    Best wishes,
    
    Jakob