I don't think so. If the REST server is part of a larger system then I believe that the AGPL requires that the other networked software components need to be AGPLed.
They do have a commercial license (I think that they charge $1K for a 1-server perpetual commercial non-AGPL license).
How about if the Neo4J REST component was (say) one of a few options (the others being something like FlockDB or a mysql implementation)... In effect you would need to bring your own Neo4J platform to use the larger sytem, and Neo4J would not be a core component of it.
Good point, but I am not sure. The key thing is to respect the wishes of the authors of a package so I would just contact the Neo4j developers and ask them.