It is revealed that Mrs. Schultz is named Greta, a diminutive of Margrethe. Since it is previously known that Sgt Schultz is named Hans, a diminutive of Johannes, together the Schultzes are quite literally Hansel and Gretel.
UPDATE: Cute story, but Barbara Morrison is credited as Gretchen Schultz, and John Banner does call her "Gretchen" when Schultz greets her. It is a drawn-out pronunciation ("Greht-chaaan!"), but he does pronounce the "n" at the end. Getting to Gretel from Gretchen is more of a stretch than it is from Greta, with the hard "n" sound distinctly different from the hard "l" sound.
UPDATE: Cute story, but Barbara Morrison is credited as Gretchen Schultz, and John Banner does call her "Gretchen" when Schultz greets her. It is a drawn-out pronunciation ("Greht-chaaan!"), but he does pronounce the "n" at the end. Getting to Gretel from Gretchen is more of a stretch than it is from Greta, with the hard "n" sound distinctly different from the hard "l" sound.
Sgt Schultz's hometown is Heidelberg.
Klink mentions to the Doctor that Schultz is clearly only in his forties. John Banner was 57 when this episode aired.
It would seem Schultz did get a divorce from Gretchen. Schultz never mentions being married again.
This is one episode where Carter is in the credits, but does not appear in the show.