Gretchen means pearl. That will not work with this machine.
Chrysta short for Christina meaning Christ-bearer.
Mum short for Mutter, mother.
Seriously now:
Aster or Ester meaning golden, since the chrysanthemum is in the Asteraceae family, just use the Aster, but change to Ester. Ester isn't German, but that was the closest I could get to a girls name that had to do with flower and chrysanthemum.
Michaela, feminine form of Michael which means "who is like God", since Pfaff's name was George Michael (isn't that a singer)
Lena, after Lena Pfaff who took over the business after 1919.
Ulla, meaning willful or deliberate.
Wanda, wanderer, (who knows where this machine has been).
Amelia, hard working (which all Pfaff's are)
Chrysta form of Christina which is Christ bearer ( goes with the Legend of Chrysanthemum)
Elsa, noble (your machine looks noble)
Emily, industrious hard working ( yup, that's a Pfaff)
Winola, charming friend (looks to be that type of machine, you can tell her your deeps secrets and she will never tell
).