The main character in this book is Matt Carlton, the leader of the Adventure Club. His friends are Katie, Hooter, Quentin, and Tony. Israel is a soldier in the Continental Army that Matt meets along the way during their adventure. Some characteristics of each are:
Matt Carlton - Good leader, brave, kind and generous, loves his family and friends, adventurous, "The Leader" (Adventure Club name)
Katie - Kind, adventurous, fun, cool, Matt's younger sister
Hooter - Nice, shy, very kind-hearted, "Strong Man" (Adventure Club name)
Quentin - Careful, nice, "The Club's Brain" (Adventure Club)
Tony - Smart, very small, good friend, knows what it's like to feel left out, "The Scout" (Adventure Club)
Israel - Very kind, loves his family, injured during the war, dies from infected wound
Hope this helps! What a great book!