If I enter a dynamic on a note and then, in engrave mode, move the dynamic some distance away (like to the end of a long tied note), will playback reflect its new position or the original position?
Original position. That’s precisely the difference between Engrave and Write mode. In Engrave mode, only the visual appearance is changed, not the “data.”
If you drag the dynamic around, you’ll see the dotted line keeps the dynamic anchored to the same position.
It will reflect the original position.
In write mode, if you drag the dynamic you will move its attachment point shown by the red dotted lines.
If you want a dynamic to start part way through a note, position the note input cursor and then create the dynamic. It will be attached to the rhythmic position of the cursor.