In my opinion:
- "In classic Onion architecture, the core is referenced only by the next layer."
That is not true, Core should be reference by any layer... remember that Direction of dependency between layers is toward the center (Core).
"the layers above can use any layer beneath them" By Jeffrey Palermo http://jeffreypalermo.com/blog/the-onion-architecture-part-3/
- About your EF, it is in the wrong place.... it should be in the Infrastructure layer not in the Core layer. And use POCO Generator to create the entities (POCO classes) in Core/Model. Or use a Auto-mapper so you can map Core Model (Business objects) to Entity Model (EF Entities)
