Ha haa, really interesting in fact, the "low end pissing contest" is one thing, nothing new about that, but the whitecaps topic is another.
And drsurf is correct, very stable seabreeze winds can have loads of power, compared to more "cheasy" wind.
Wont comment on the "how low can you go", but whitecaps
In my experience:
Whitecaps starts in miniature to be seen widespread and very rare, in 8-10 knots.
In 14 knots it is what we call just covered with whitecaps (meaning all over and quite okay wind).
In Danish we call this "Kattepoter" which translated means "Cat Paws".
BUT, the visual around 8-10 knots depends hugely on the sun too, as if sunny, you can see these glimpses of whitecaps a lot earlier and be tricked into thinking there is wind, maybe even in 7 knots yes, where there isnt wind.
And opposite, if overcast, a bit more wind is needed till it looks like rare whitecaps.
The very water surface can also influence how early/late whitecaps start, so if it HAS been windy t.ex, and less wind now, there can easily be lots of whitecaps from the water "tops", cresting in less wind than usual now.
Besides shear wind (wind layers), wind gradient, and turbulent wind of course.
Meaning, in my experience on open sea during the last +40 years, whitecaps depending on conditions and how you define it, can be in the range 7 to 15 knots depending on sun and sea state and how covered you want them.
But they most often start in 9-10 knots here.
Current does not change whitecaps, as we ride in the same water as the surface, so wind has to be measured/felt relative to the water of course, not land.
As this determines how early we can start