I agree with CrazyG. The AI syncs with the bonus Longhouse production very well, especially when it goes Progress and gets Food/Culture from completing buildings. And as you (PapaRockett) pointed out, Hiawatha's AI likes to chop down trees a little too much, and since the capital placement algorithm tends to place Hiawatha in heavily forested regions, that bonus production from cutting forests feeds into the building completion, so he can fill out his non-capital cities with buildings faster. This boost only lasts for as long as he still has forests/jungle around, but in the early game he tends to jump ahead. Also, yes, his AI is good about handling war/peace relationships with other Civs. I've seen this behavior again and again with the Iroquois in my games over the last several months of patches, even after his forest-chopping tendencies were trimmed back (heh) a few patches ago.