Relation to column is OK, if necessary, one can edit the label and the marker manually.
e.g.
To add some dummy entries for "name":
1) add a Points Overlay and deselect all Variables but "Color = Name".
The idea: don't show any data point - just create new entries in the legend for every "name".
[for all the other plots, deselect "Color = Name" to keep them as they are]
2) In the legend, adjust the marker/color to the settings from row states
... and deselect unwanted entries