The characters played by Leonard Altobell and Dorothy Keller are named Walter and Lillian Elias respectively. Walt Disney's middle name was Elias and his wife's name was Lillian.
In this movie, the daughter of Sharon Ferris, one of Hayley Mills' characters, is named Nikki Ferris. Mills' character in La baie aux émeraudes (1964) also had that name, although Mills' character spelled her first name "Nikky" instead of "Nikki".
Several of the character names in this movie are references to Hayley Mills' subsequent Disney works. Susan's married name Carey was the family name in L'été magique (1963). Mary Grant (changed to Grand for this film) was her character in Les Enfants du capitaine Grant (1962), and Nikki (or Nikky) Ferris was her character in La baie aux émeraudes (1964).