Aren't we making this a lot more complicated than need be?
A case of some common-sense which includes, if there is any ambiguity, telling ATC what you intend to do, or asking them what they want you to do?
After all, if you're "visual", chances are good that whether or not you proceed to the pattern altitude or the MA altitude you should otherwise be able to see where you're going and therefore avoid both other traffic and obstacles...especially if you've got TCAS and EGPWS as well.
In addition, I have a problem with, having declared being "visual", then placing the aircraft in a position where I'm no longer visual. I can see all kinds of folk getting upset about that, rightly so IMHO. In this case, I'd be onto tower in advance seeking clarification one way or the other.
As for tower not knowing what you're doing, can't they look out of the window as well?
So if you're shooting visuals when the cloudbase is below MA altitude I can see things become a little problematic.
As for the EO case, 9.G said it all...you have to have an idea of both your EO landing performance and your EO GA performance a priori with the situation becoming potentially more and more serious as you proceed below various minima.