Violence: Alcatraz and the Rithmatist are the least violent. Steelheart is nearly as violent as Brandon’s adult books, and may be considered more violent by some since Steelheart’s violence uses guns and the other books largely have magical violence or swords. The Mistborn books were originally written for an adult audience, but the content is as appropriate for teens as Steelheart. They contain fantasy violence.
Sexual content: There is nothing onscreen in any of the books. Warbreaker has the most sexual topics as conceiving an heir is a major plot point. In the Stormlight Archive there are a couple of references to whores that follow the army.