Tabitha has a pet fish in her room. His inclusion in the movie was because director Tom McGrath, had lost his own beloved pet fish of 10 years shortly after the first Boss Baby was wrapping up and thought it was a nice way to honor his memory.
James Marsden replaces Tobey Maguire for the voice of Adult Tim in this sequel, due to Maguire busy working on Spider Man: No Way Home. Maguire had been cast as a replacement for Patton Oswalt in The Boss Baby (2017).
When the meeting is called to order in Tina's room, the notes Tina plays on her xylophone are the same tones used for NBC. NBCUniversal is the parent company of DreamWorks Animation.
In the epilogue of the original film, the adult Tim and Ted were only shown from the chest down, due to their younger selves being the main focus. The older versions are now promoted to being the main characters in Family Business, so their faces are fully shown.
As Tim walks towards the Ted during recess viewers of the sleeper hit film Shawshank Redemption will hear the familiar into music as Tim Robbins' character Andy Dufrane is being bussed into Shawshank prison, being played by the baby with a violin.