After digitizing several works by now, we found as much as 10 different edge types in the drawings and use four classifications of nodes. Here, aside from persons and institutions, years in timelines became necessary and we use an extra class for the descriptions on when a player in the story exists by some external event. The is reflected by the new version of lombardi.owl.
We also started to link to external ontologies for persons, institutions and years, preparing to contribute all of this as llinked open data.
We use Protégé as our ontology editor and can generate the following visualization of the ontology.