Make soup: Heat oil in a wide 5- to 6-qt. pot over medium-high heat. Add squash, yellow onion, pear, 1 tsp. salt, and the pepper. Sauté until squash starts to brown, 15 to 20 minutes.
Add broth, cover, and bring to a boil. Reduce heat to a simmer and cook until squash is tender, 10 to 15 minutes. Remove from heat.
Add half-and-half and almond butter to broth mixture. Whirl soup in batches in a blender until very smooth. Return soup to pot and cover.
Make topping: In a medium bowl, gently toss together radishes, green onions, pumpkin seeds, feta, and chile.
Reheat soup just to a simmer, if needed. Stir in lime juice and brown sugar, and add more salt to taste if you like. Ladle into bowls and serve with topping and lime wedges.