William,
I don't see any quick&simple solution.
You can create string parameter PARYESNO in your models and put Yes/No value in it manually and show the parameter value in the Repeat region.
You can use Search tool in Assembly mode and find Included components using rule Relation is equal to Unplaced. Then you can select all found models, press RMB in Model Tree and use Edit Parameters command. Then you can modify the value of PARYESNO parameters in single window.
You can also create a layer defined by rule Relation is equal to Unplaced.
Martin Hanak
