Can't get Continuous to work on my Rigidbody2D

What do you mean by this? No collision whatsoever, ever or intermittent collision tunneling? If no collisions ever then that's nothing to do with the collision mode.

Those have nothing whatsoever to do with continuous col-det so ignore them.

Continuous only works on non-triggers. Also ensure you're not respositioning the Rigidbody2D at all either directly or indirectly via changing the Transform in any way.

 

I'll assume then that it's not to do with the above I posted.

So this isn't to do with "Continuous" collision mode specifically then. Check that the collider layers are set to contact each other in the physics settings.

There's no rule about having a Rigidbody2D, you should simply know what not having a Rigidbody(2D) means which is that it's a static (non-moving) colliders. You can add a Rigidbody2D and set it to be a static body-type too which would be more or less the same thing. What is important is that certain body-types can only contact specific body-types i.e. static do not contact other static which makes sense because they're not supposed to move. The detail in the manual should hopefully not be ambiguous in this regard here.

No, continuous applies to that body only and selecting the option on one body is all that is required.

It's impossible to answer questions like this as there are too many variables in such a set-up. The best way is to do a simple prototype and check the profiler to see if your approach scales. Any answer I give will be adjusted by the real world results on a specific device.