I used to use the workflow create feature class from lines and populate my polygons with subtypes from a point feature class with ArcMap 10. I have just moved to Arcmap Pro, and have used the replacement workflow of Polygons from Lines which allows for the creation of labels generated from the point feature class but does not populate the new polygon feature class with subtypes. As a result, my map labels cannot be easily managed in the label class workflow presented by Arcmap Pro.
To overcome this I am trying to write an expression for the Label Class which I can copy to future iterations of my polygon feature class. It is a geological map with unit type names, the field [Type] holds numerical identifiers, but the text code is now stored as a symbology class identifier and not a field.