I cannot speak to your question about multi-tenancy, except for what I currently do to enable that scenario in Neo4j 3.x. The beauty of being schema-less and leverging what we can do now is that I have three graphs in one database. For instance, one graph contains my 'Library' data, the other 'Language' data--these are two unrelated data sources, which share a 'Common' graph that is compose of referential data shared by the other two. All nodes and edges have one of these three labels, which acts as a schema identifier since my data interacts with PostgreSQL Each node also has another label denoting the first degree of identity, such as 'Person" etc. and each edge has its corresponding label as well. This makes the Cypher statements easier to manage and to work with the data. So at the very least I have three separate graphs in one instance of Neo4j.you could do something l;ike this until Neo Tech comes up with the official methodology that provide 'schema-like' structures in Neo4j in the future.
Demystifying Neo4j UX Research
