Very minimal. A few mild exclamations like 'butt' and possibly 'dang' or 'heck.' No profanity of note. Some potty humor typical of children's animation.
Cartoon/slapstick violence throughout. Characters are captured and held in a diamond prison that drains their talent (shown as physically weakening). The villains squeeze musical talent out of trolls, which causes them visible distress and could be mildly scary for very young viewers. Chase sequences, physical comedy with pratfalls, and a climactic battle scene — all stylized and non-graphic. No blood or realistic injury.
Mild romantic subplot between Branch and Poppy — they share a kiss. Some very light flirtatious humor. One brief joke references a 'baby' troll in a way that gets a double-take reaction (played for comedy). Velvet and Veneer, the villains, wear flashy pop-star outfits that are somewhat form-fitting but nothing inappropriate for the animated style. Overall very tame.
The troll world operates on a fantasy logic where music has magical power — singing can produce literal energy, color, and light. This is consistent with the franchise's whimsical worldbuilding and is not rooted in occult practice. The villains harvest musical 'talent' as a magical substance. This is more akin to fairy-tale fantasy than occult empowerment.
Strong themes of family loyalty, brotherhood, forgiveness, and reconciliation. Branch must overcome hurt and bitterness from being abandoned by his brothers to reunite with them. The film teaches that family bonds are worth fighting for even when they've been broken. Self-sacrifice is modeled when characters risk themselves for each other. The villains' obsession with fame and talent-theft is shown as clearly wrong and ultimately leads to their downfall. Authenticity and being true to who you are is valued over superficial celebrity.
When Branch's brother, Floyd, is kidnapped for his musical talents by a pair of nefarious pop-star villains, Branch and Poppy embark on a harrowing and emotional journey to reunite the other brothers and rescue Floyd from a fate even worse than pop-culture obscurity.