For the pepita-coconut-lime garnish, preheat the oven to 325°F.
Toss the pepitas with the oil and spread them on a rimmed baking sheet. Toast in the oven for about 6 minutes, stirring once or twice to encourage even browning. Transfer to a cool plate to stop the cooking. Keep the oven on.
Spread the coconut on a rimmed baking sheet and toast in the oven for about 10 minutes, or until browned around the edges. Transfer to a cool plate.
In a small bowl, toss the squash with the yuzu juice and season with salt.
Grate the zest from the lime or peel and chop it. Peel the pith from the lime and slice the lime into thin rounds.
For the soup, in a stockpot, heat the oil over medium-high heat. When hot, add the lemongrass, onion, and ginger and cook, stirring, for about 1 minute, or until they soften slightly. Add the garlic and continue to stir for another minute or so until softened. Take care that the garlic does not burn.
Add the squash and the vegetable broth. The broth should cover the squash by about ½ inch—if not, add a little water. Let the broth come to a gentle boil and then reduce the heat and simmer for about 20 minutes, or until the squash is tender when pierced with a fork.
Working in batches and using a slotted spoon, transfer the squash and other vegetables to a blender in small, manageable amounts. Puree until smooth and add liquid from the pot to adjust the consistency.
As each batch of soup is pureed, transfer it to a clean pot. Add the lime juice and salt and stir to mix. Taste and adjust the seasoning, if necessary. Serve garnished with the toasted pepitas, coconut, squash, lime zest, and lime rounds.