Despite of my newbie status on the list, let me ask back:
What's your intention with separating dynamics, the notes and the
fingerings?
If the separation is only for displaying purposes in a specific staff, I
would simply remove the corresponding engravers from the voice
\remove "Dynamic_engraver"
\remove "Fingering_engraver"
No, the reason is not for displaying purpose. (For that you can also use \omit Fingering in front of a music _expression_).
The reason is that music and fingering are two different things. You don't always need both. And sometimes you need multiple fingering for different instruments or different "hand" etc.
Thank you Stephan!