I think the great peacemaker is uncontroversially seen as a historical figure (sort of similar to Jesus was probably a dude) but while Jesus said really nice stuff they're better known for miracle stuff... the great peacemaker does have some miracles like crossing a lake on a granite canoe but most of what he did was negotiating the peace to unite the confederacy. All that stuff he did is probably historically accurate with the miracles likely being embellishments over time.
Also the great peacemaker and the creator and their twin are distinct figures. It sounds like you understand that but I just wanted to clarify that.