It doesn't need to be distributed, and it's better not to include that because the approach to error handling gets a lot easier. If you're distributed every call can fail, be randomly slow, has marshaling costs, is untrusted, etc.
Yes, Goblins' "vat" model descends from E, which supports the "hybrid worldview". http://www.erights.org/
I have a tendency to call Goblins objects "actors", though some people in the community like to point out that "distributed object" is preferable since synchronous call/return is not supported in actors. But yeah.
Sure, you can do async request/response in the actor model, but the low-level basic mechanism all communication is built on is send a message to an actor mailbox and keep going. Everything else is built in top of that.
While the implementation in many popular, e.g. C++ and family descended from it, languages muddies the waters, basically methods in OO are a convenient way to define handlers for messages sent to objects, and in pure OO you also can't interact with objects except by sending messages to them. The difference between the basic OO model and the actor model is that OO message sends are synchronous request/response and actor model message sends are asynchronous fire-and-forget.