I'll go with that...
Voodoo, Vaudou, .Is it just because the spelling is different?
First, Voodoo in Africa is only located and sometimes still practised in the Bight of Benin ( mainly in Benin or Ancient Dahomey, and Togo), so if you say that you saw Vodoo/ Vaudou all other Africa , it must be a mistake because they don't practise Voodoo/Vaudou outside those two countries, and if it the case it is surely an importation (or due to migration of people) because Vodoun belongs and originates to / from Benin/Togo.
Second, Vodoo in Africa is the original form, and Voodoo in Haiti in a syncretism between the different groups deported there : Araras ( those to which belonged Vodoo in Benin), Congos, Senegambians ( who were mostly muslims), Nigerians etc. Hence you have some muslim loas in the Haitian Vodoo ( according to Alfred M?traux), which is quite impossible in the Voodoo practised in actual Benin or Togo.
The same can be said of all the religious/spirituals forms found in all the Iberians salve colonies : Brazil (Candombl?), Cuba (Santeria), Puerto Rico (Santeria) , DR ( Santeria and Dominican Vudu) etc, their forms have been influenced by the biggest slave group.
The Cuban Santeria is mostly influenced by Nigerian creeds ( Shango, Yemanya etc)
The Dominican Santeria is mostly influenced by Bantus believes ( Congos / Angolas)
The Brazilian Candombl? is also influenced by Bantus (Angola/Congo) and Nigerian creeds.
Africans deported into the new world, created new forms compared to the original forms of Africa , which have been modified with "Europeans" inputs like Christianity (in quotes, knowing that Christianity reached Africa before Europe) and also Native Indians inputs ( like for the Dominican Vudu,where you can find native indians loas).