Oddly enough, I was also in Dominica at the time. I don't remember hearing anything about that "national street party", but everyone I came in contact with immediately after 9/11 was incredibly kind and most seemed more emotionally affected than I myself felt.
Dominica or Dominican Republic? I mean Dominica... Wandered into Roseau, there were people literally dancing in the street - asked what the occasion was and that was the response. All the cruise passengers stayed on their ships from what we could tell.