I know this is an old discussion, just a newbie trying things out here.
Hmmm...interesting theory, but I am not sure if the Pilgrims ever had a pre-search party sent out to scout a place for them to come to before they ever left England.
Besides, they ended up landing in the wrong place, bad weather, bad directions etc.
I am not saying the Europeans didn't bring the diseases you mention, but the Pilgrims were certainly not the first ones to bring such diseases with them to the shores of the US. That may have started with Columbus!