Fun random stuff from the "With Six You Get Eggroll" wiki page:
Blended family premise
The film was released only four months after United Artists' Yours, Mine and Ours. While both films have the same premise—that of a widow and a widower marrying each other and creating a blended family—the United Artists film was based on a true story and was a huge commercial success (if not critical) becoming the 11th highest-grossing film of the year.
Although there are similarities between this film [ meaning ...Eggroll ] , Yours, Mine and Ours and the later ABC television show The Brady Bunch that premiered in 1969, the original pilot script for The Brady Bunch predated the scripts for both of these films.