Billy Connolly admitted in an interview that when he was offered the role of Lord Dargis in this sequel, he wasn't aware that the first Garfield (2004) movie existed.
The voice of Garfield in the movie (Bill Murray) was originally voiced by Lorenzo Music in the Garfield TV shorts and movies released in the 80's. Lorenzo Music was also the voice of Dr. Peter Venkman in the TV cartoon series, "The Real Ghostbusters", for the first season. Dr. Peter Venkman was originally played in "Ghostbusters" by Bill Murray.
When Dargis is talking to Liz in the kitchen, he is wearing a brown suit. He then leaves the kitchen in pursuit of Garfield, and the next scene shows him in a black jacket and gray pants. There was no time to change clothes.
When Rommel is chasing Dargis after the animals fire the clay
launcher at him, Dargis falls to the ground and looks behind him. As Rommel comes bounding around the corner, there are three people visible next to a stone sculpture. The camera switches to Dargis, and when the camera goes back to Rodney, the people are gone.
When Prince comes out of the sewer, he's shaking some of the dirt off him. When it zooms out right when the humans come by, the dirt disappears, and then re-appears when it zooms back on Prince and Odie.