This will be your second war. Unlike your first this will be of an inevitably wider scope, with multiple enemies to dispatch. There are a few options of whose territory to open to Elysian settlers. The compromise with the barbaroi councils after the conquest of the Tuscarora has shown that with autonomy even the barbaroi are unwilling to rebel for the power to eject Elysian settlers or prevent the extraction of natural resources. This will provide those resources and avenues for expansion, but most importantly it will remove threats to Elysia itself.
[ ] Lenape, Erie, and Monongehala. While the Lenape have failed to adapt to the times, and the Erie lag at least a decade behind the innovations of your subjects the Piscataway, the Monogehela are a larger tribe in direct contact with your subjects, and as a result of their larger size have a certain organisational bent that mirrors Elysia's doctrines - in a way. While your forces are supremely organised, the Monongehela have developed the art of the ambush to a fine art. This 'triple alliance' of tribes will result in two fronts - one in the north, and one in the west. All told you will likely be facing around ten thousand angry natives in two major groups, which will require splitting your own army to prevent them rampaging through the Elysian heartland.
[ ] Susquehannock, Tutelo, and Ponca. These three tribes have been more isolationist than not, and as a result Tutelo is completely unprepared to fight on terms with the Elysian army. Susquehannock is a little better, but attempting to catch up to the doctrines of Diogenes is not enough anymore. The true threat in the war will be Ponca, which has developed a surprising population after settling into a sedentary lifestyle. This small tribe can probably muster five to six thousand warriors, more than half the forces of Tutelo and Susquehannock combined. The north and west fronts will require splitting your forces, but you predict an easy victory. One might argue that this easy victory is exactly why they shouldn't be the target, but you can't argue with success.