the normal modes don't trigger much of anything because they are miniscule, and the longest period ones are not the largest, although they do tend to persist the longest. The tides are FAR larger than most of the normal modes for most earthquakes, and much longer period (which should boost their effectiveness triggering earthquakes) and even the tides don't do much.

If Ecuador lit up, it would be simplest to point to geometric concentration of energy at the antipode, not normal modes.

Surface waves are just another way of describing the motion of the Earth, and are most convenient for time intervals much longer than the Earth's resonances, which are less than an hour.

Not sure there is ANY evidence for FFA. Certainly there's none that I've seen.

John