it's made clearer in this movie that Fleet and Claudette are in love. at the start of the movie, Claudette has a flashback of how she and Fleet used to train for the great games together. after this, she's murring and kissing the air while the others uncomfortably stare at her, and Runt starts teasing.
Humphrey's about to tell the pups how he "was about to put the moves on Kate", but Kate stops him before he says anything else.
Kate and Humphrey are about to kiss, but they're stop halfway through by Brent, who needs to pee.