Roger,
So my first question is: How do we develop a core vocabulary/ontology in a distributed, collaborative way?
In the absence of a more sophisticated tool (free, open source, capable of exporting models in different useful formats, allowing collaborative work, etc.) a wiki should be fine.
Regarding documentation, a mix between the CIDOC and DublinCore approaches sounds good.
My second question is: Can we separate the definition of terms from the ontologies?
If I understood correctly, the question is "which level of detail should we address?". I think we should start as simple as possible, maybe not trying to address constraints that look too specific, but also not leaving everything "independent" (links are important). We could define the main classes and properties from different parts of the ontology. Then we could try to represent them in some format, create instances, experiment alternatives of integration and extension, etc. -- Renato