well, there were shamanistic religions in europe before misguided christians stomped them (celts, germans before karl the great, slavs for instance), if you want to avoid being accused of "white-washing", try to portray different members of the cultures in question different depending on who they are, what influenced them during their lifetime and so forth.
for instance, you could have a joung, druid-like charakter in it who questions the voodoo-thing, while you could have a black- or asian-like scholar who ventures the lands on the search for answers to all the big questions who came from some kind of monotheistic, work-for-your-salvation-religion, which may or may be not the original religion of his or her people.
try to untie your world building from our world, rather try to portray your characters as human as possible since you only use humans, make religion a part of their personality, but not the be-all-end-all, most people in reality believe in some things without letting every possible decesion guide by thoose believs.
think about it this way, even today there are christians who rather pray to mother mary than jesus or god, despite it going against the doctrine of pretty every christian sect, on the other hand catholics are required by the teachings of the popes to believe in angels for which they get frequently criticized by muslim scholars who believe that this makes catholizism a polytheistic rather than a monotheistic religion.