Chinese don’t expect non-chinese to understand or follow their customs exactly.
So, Any gesture or gift you give will be appreciated. Especially if these folks are >50 years old, a nicely decorated gift-box of something is common given in China by visitors - nuts/dried fruit, wine, fresh fruit, chocolates.
Try to make it RED color. RED is the color of luck and New Years (not communism!)
Is a red gift bag appropriate?
How do I address the family? I have never met them and want to be respectful.