Gastineau rhymes with:
martineau, babineau, babineaux, barrineau, cousineau, martineau, mullineaux, papineau, albino, altiplano, babineau, babineaux, barrineau, carbonneau, charbonneau, cousineau, domino, galarneau, guano, lessnau, martineau, molineaux, mullineaux, oregano, papineau, pocono, pompano, rhino, romano, sesno, winnow
Gastineau sounds like:
gaddum, gaetano, gaitan, gaston, gastonia, gathman, gatien, gatten, gatton, gaudin, gaudino, gautney, gayden, gaytan, gayton, gedeon, gedney, geodyne, gestation, getman, gettin', gettman, gideon, gidney, gitana, gitano, goddam, goddamn, godden, godin, godina, godine, godino, godman, godown, godwin, goeden, gooden, goodenow, goodin, goodine, goodman, goodnow, goodwin, goodwine, goodwyn, gosdin, gotham, gotten, gottman, gudino, guidone, gustin, guston, gutman, gutmann, guttman, guttmann, gutwein, guyton, gyohten