Detailed below are suggestions for how the archetypal characters from Treasure Hunter Adventures could be used to play kids similar to those in Finding 'Ohana and The Goonies. The chief modification to make is replacing the Archetypes' various Hindrances with Young (SWADE page 28), meaning that they must reduce one Attribute and two Skills. In fact, that's a good opportunity to reduce or eliminate Skills that might be inappropriate for a character of that age. Additionally, they'll need new starting equipment to represent their youthful possessions.
Types of Kids
These kids are quick and agile, and probably enjoy putting those qualities to the test. This could just be seeking thrills, or it might be to provide for oneself and others.
Pili is a good example of this, having honed her skills in competitive geocaching.
Big Kid, Athlete
Some might be big and strong for their age, while others are just older. Either way, they are good at moving heavy things.
Eoannes and Brandon both fit this role as the older brothers.
Farm Kid, Older Kid
While it might seem unusual, sometimes it's necessary to advance the plot. This could be a farm kid who learned at a young age because it was needed.
Hana argaubly plays this part, even if her skills aren't really put to the test.
Boy or Girl Scout
This kid knows all about the natural world, and feels quite comfortable being outdoors for long periods of time—even overnight.
Although Casper might initially seem more like a nerd, his knowledge of nature and reverence for Hawaii match up here.
Popular Kid, Natural Leader
Charisma is what helps this kid navigate life. This can play out like a fast-talker, a comedian, or someone who is sincere and idealistic.
Mikey, Mouth and Chunk all play this role in different ways. Mikey is idealistic, Mouth is convincing, and Chunk is funny.
Inventor or Nerd
This kid knows a lot about some specific topics, usually ones that are useful in regard to the storyline.
Data fits this role, especially with his gadgets such as bully blinders, slick shoes and pincers of power.