For what it is worth, you can find the precursors to any of the forms that you see emphasised more in America in Japanese Zen. For example, the lay practice you could be compared the Ningen Zen movement/organization in Japan. For social activism, there have been many examples of individual monks who took strong social stands.Is there a distinct “American Zen”? And if there is, how would you describe it?
The flavor of Zen in America can't be pinned down to a single set of attributes because it is a fluid activity done by people who are also changing. Yet, the environment is different so the form adapts to the environment in some common ways.
In my not strongly held opinion, the following factors help give American Zen its flavor:
- Large lay practices
- Social activism
- Little budget for "Zen" architecture like the historical temples in Japan or China - meaning much practice is utilitarian
- Few Americans have a Buddhist studies background which many (most?) new monks have before starting their training in Japan
- Few Americans have a knowledge of Chinese characters which makes directly accessing Chinese texts more difficult
- Blending with other age practices is commonplace
- Sanghas provide a social network much like a Church
- Practice is not as physically demanding and is thus far more accessible (and this is valued)
- More permissiveness in discipline
Honestly, I think the form of American Zen as much as I can articulate it is refreshing and I am appreciative of the American Zen ancestors who worked so hard to bring Zen across the water.