Hanging a heavy edgeless mirror so that it tilts down
Not sure about how well it is for earthquakes, but for better security, I'd go with hinges at the bottom, instead of cleats. That would provide less chance of mirror jumping from its position during a minor earthquake, and also wouldn't bruise the wall during angle change, if the hinge is hanged at the very bottom of frame.

For top I would go with with D-ring free-angled bolt anchors in the wall, something on these lines:



, with D-rings at the top of the mirror frame (as you said), and appropriate thickness chains linking the two. This would also provide for easy change of mirror angle -- just control the angle by inserting pins or similar fasteners in appropriate links of the chains.

As a bonus, nothing should be visible from front of the mirror.