These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Tom and Jerry also talked and sang occasionally in the original shorts.
The Scrappy: All of the new characters created for this movie; Pugsy, Frankie, Aunt Figg, Lickboot, Captain Kiddie, Squawk, Dr. Applecheeks... and especially Robyn Starling, the girl that Tom and Jerry help to find her lost father, and the one responsible for making Tom and Jerry stay Out of Focus and making the movie being about Tom & Jerry In Name Only. The few that aren't universally reviled (Lickboot, Applecheeks to name a few) are only liked because of YouTube Poopremixes and memes.
Pugsy deserves a special mention, as he is the one who got Tom and Jerry to talk and sing about how they are best friends, despite Tom and Jerry being, you know, mortal enemies.
Squick: Aunt Figg and Mr. Lickboot look like they're about to kiss at the end of their Villain Song.