Kate was previously played by Parisa Fitz-Henley in "My Spy", she is now being played by Lara Babalola.
The name on the surveillance van they find in the safe home in Italy, "Morricone idraulici", it's a Nod to the famous Italian film music Composer Ennio Morricone
Kristin Schaal and Ken Jeong both appear on Bob's Burgers as Louise Belcher and Dr. Yapp respectively
When talking to David about why he can't go back in the field, JJ tells him "I just want to be the best guardian". This could be a nod to the fact that Dave Bautista is Drax in Guardians of the galaxy.