Parallella Community

Unless I'm misunderstanding you, OpenCL 2.0 already supports this with Pipes.

A1. In 2.0, it's very explicit with pipes, but yes.

A2. It was on their roadmap a while ago. Actual implementations may vary.

A3. I wouldn't expect many improvements to the Epiphany OpenCL stack anytime soon unless the community does it. The OpenCL device model just doesn't map well to the Epiphany architecture and others like it.