Nemo_bis
(Nemo Bis)
3
One way to make such splits less painful for data consumers is to make sure that any relevant data is carried over to the new items.
First of all, the translations of the names in all languages need to be copied over to the new Wikidata items.
Second, links from OSM to Wikipedia need to be added. The Frankland River relation now only links a Wikidata item without sitelinks to Wikipedia; it should also have a link to all the Wikipedia articles previously linked by the linked item, given the two concepts are merged on Wikipedia. The Frankland River node has a link to the English Wikipedia article only but not to the other languages (this may be fine).
Third, links from Wikipedia to OSM need to somehow be handled. Linking the node is clearly not what is needed for the Wikipedia article, as you need to zoom out to get an idea of the place. Linking the relation is an easy way to zoom the map correctly and show both the boundaries and the place name with a single URL. Is there a way to link the node and have osm.org also show the boundary and zoom in correctly? If not, the link to the node needs to be supplemented by a link to the relation.
Fourth, and more generally, Wikipedia and other consumers of the data which previously used the item to pull up data about the map of the area need to be provided the new way of accessing the data. I’m not sure how to handle this on the English Wikipedia in general, but in this specific case the infobox allowed to specify a new Wikidata ID. Given this is a common need it would be best for the Wikidata item to provide this kind of preferred map URL to avoid reducing the usefulness of the Wikidata items: maybe a new property is needed?