@George: The sources are certainly to matters outside of this project's limits. And, yes, I have been known to go off on tangents - one of my favorite moves, in fact. I'll try to be good, or at least non-disruptive.
So, as an off-topic aside, The American Mohammedan Society was established in Brooklyn in 1907 by (according to A History of Islam in America: From the New World to the New World Order, by Kambiz GhaneaBassiri) Muslim immigrants from Poland, Russia, and Lithuania. The organization (with mosque) still exists, but, is 250 years too late for our purposes here. I'll see how far back I can push things and still be able to pretend to be gainfully employed.
@Erica: It does seem reasonable to speculate that any Muslims that ended up in New Amsterdam during this project's study period would have met informally. It also seems reasonable, given the problems the government of New Amsterdam periodically decided to have with Quakers and Jews, that they'd do their best to stay out of said government's view. Which is to say, I'd be happily surprised if there were any documentation that moves any of this beyond speculation.