The plot of this movie is based on the idea that the fate of Carol's first husband is never mentioned in the original TV series. In the series pilot, it is implied that Mr. Brady's first wife is deceased.
Tim Matheson, the man pretending to be Carol's first husband, played Mike Beardsley, the oldest son, in Yours, Mine and Ours (1968), the inspiration for the original The Brady Bunch (1969).
In the scene that takes place at the construction site, the signs in the background read "Reed Design" - no doubt a tribute to the late Robert Reed, the original Mike Brady.
At the airport in Hawaii, when Mike Brady is talking to the rest of the family, he is shown standing just in front of the aircraft's wing; in the shot looking the opposite way towards the rest of the family, nearly the entire aircraft is in the background, clearly showing them standing well behind the wing.
When Peter hits Mr. Phillips at the office with the nunchucks, he hits him on the top of his head. But later at the construction site the swelling on his head is above his right eye.
The pamphlet with the adult number that Jan calls to pretend its George has the phone number 555-HUNK written on it. She is seen dialing the number "1" 3 times which does not correspond to the last 3 letters in HUNK (UNK).