This sums it up perfectly.
Another thing that has been ignored so far, is that the first native attacks on the first norse settlement attempt was caused by a bull run loose (which apparently trampled a native and started the first fight).
uh... huh? I'm looking through my copy of "The Vinland Sagas" (specifically, the Greenlanders' Saga), and the chapter on Karlsefni's colony notes that the bull just scared the natives by bellowing. The fight was caused by a native trying to steal some of the Norse weapons (something I can believe.. the natives weren't stupid, and would have seen the value of the steel right away). The native got killed for his efforts, and the natives attacked later. "Erik's Saga" (a tale I regard as a lot more dubious, due to the heavy mention of Christianity and some weird stuff like Unipeds being added in) mentions that the natives were also scared by the bull, and that they attacked later because of it. Neither mentions a native being trampled by the bull. Come to think of it, if you're looking for a reason for Norse/native conflict in this POD, the natives trying to steal tools or weapons or livestock would do it...