I think this is a very good idea. Solid and simple and using the UA´s in the same way as they were used before - to show the way.Say,
what if the UAs scan the system for Barnacles after being dropped. If no barnacle is found, the UA points to Merope and transmits its data.
In case a Barnacle is detected in the system, the UA could orient itself towards it.
Just an idea, but did we drop a UA in every of the seven sisters and checked, if the UA point to Merope? It does in Merope and Maia, but that must be true for every star system in the Pleiades.