Wallenberg's rhymes with:
hoffenberg's, katzenberg's, rittenberg's, rosenberg's, rosenbergs, freedenberg's, greenberg's, hoffenberg's, katzenberg's, rittenberg's, rosenberg's, rosenbergs, steinberg's, thornburg's, thornburgh's, thornburghs, thornburgs
Wallenberg's sounds like:
wallenberg, willenborg, wollenberg