Cut pumpkin in half and clean out seeds. Clean seeds of remaining flesh and spread out on baking sheet. Sprinkle with olive oil, salt, pepper, and child powder. Take corn out of husks. Spread out pumpkin halves and corn on one or more baking sheets. Drizzle with olive oil, season with salt and pepper, and sprinkle with chili powder and nutmeg to taste. Be sure to roll corn around in olive oil and season all sides of corn. Roast in oven until pumpkin soft when fork is inserted and corn is slightly caramelized. Be sure to turn corn every ten minutes or so. Corn might be done sooner than pumpkin - set aside. Roast pumpkin seeds in oven until crunchy, shaking sheet from time to time.
Meanwhile, put stock in large pot. Add habanero pepper, onion cut in quarters, garlic cut in half, carrot and celery stalks cut in quarters, and bay leaves. Add salt and pepper. Add enough water to cover all vegetables and bring to a boil. Let simmer.
In a separate skillet, heat olive oil on medium-high heat. Add flour, whisking continuously to incorporate all flour into olive oil (2 tbsp butter can be substituted for olive oil for richer taste). Little by little add milk, making sure flour-oil mixture does not lump. When all milk is added, let simmer until sauce has thickened.
Scoop out pumpkin and add to stock mixture. Cut corn kernels off of ear. Reserve kernels from three ears and add the rest to stock mixture. Add thickened milk sauce to stock mixture. Stir all ingredients briefly and bring to a boil. Allow to simmer for 15-20 minutes or longer.
Working in batches, puree soup in a blender. Return all to pot and add reserved corn kernels. Heat through. Serve hot in bowl, with pumpkin seeds sprinkled on top.
For added flavor toast baguette rounds. Top with shredded manchego cheese. Place under broiler until cheese melted. Serve next to chowder.