Yes of course. That is what Bob meant when he said "what you see here". So we are using the term "vocabulary" in the same way.
I will try to clarify. (I don't care about the words, but I will try to express it in a way so we can understand each other.) Bob and I started with a proven domain ontology which we have used as a base for more than one software system, some of which are still being used daily. We are not and will not be doing anything around upper ontologies. So yes this could be considered a data model, if you prefer. In addition, Bob has many many years of domain experience in manufacturing and supply chain systems and has contributed to several international standards, including one for the domain ontology that we use. That is the main "ontological" or "data model" input to the valueflows project.
And of course now in a new process of collaboration with other participants, we are discussing and refining the model further. And Bob and I already knew we needed to do that, define a further generalization of what we implemented. The valueflows project is a great way to do that.
We are writing and generating json-ld vocabulary now. And yes, as we continue to work, we will start referencing existing vocabularies. And we would certainly consider ESSGlobal vocab as part of that, since it looks like we are trying to pull in the same direction.
We are not at all well grounded in linked open data, as you can easily tell! Bob and I are both very senior developers, with 3 + decades experience apiece. But we are complete newcomers to LOD. We have one person active in the valueflows project who is knowledgeable in LOD and is tutoring us as best he can. (It was his suggestion that we pull out our references to existing vocabs for now until we get to better understanding and have more time to research it.)
I am interested in your link. But for valueflows, I am not at all worried. Our methods may be more practical and more agile than you like, I don't know. We are happy with them, and are developing them together as we go based on our various backgrounds and desires for the project. Another project or set of people would of course be different.