Hello Teddy,
Joao is for certain a Portuguese/Brazilian name, the Estaque part (just as Estaquier) originates from the south of France, called the Provence. The name Estaquier or Estaque derives from l'Estaque, a thin landstroke between the mediterenean sea and a lagune(l'Etang de Berre), very close to a town called Martigues (where we al come from!). The oldest references are from 1600, they seemed to be Huguenots(French protestants), and some of them went(fled?) to Belgium in the 18c.