Melt butter in large stockpot over medium-low heat; add tomatoes, bell peppers, garlic, and green onions. Cook and stir frequently until tomatoes have nearly liquefied, 30 minutes to 1 hour.
Stir kidney beans, baby corn, and celery into the tomato mixture; add chili powder and lime juice and season with salt and ground black pepper. Cover and cook on low, stirring occasionally, until celery is soft but still has texture, about 1 hour.
Stir crab meat and canned tomatoes with liquid into kidney bean mixture, breaking up tomatoes in thirds with a wooden spoon. Season with salt and pepper; add brown sugar if chili tastes too salty.
Stir shrimp, scallops, and hearts of palm into chili; cook until shrimp are bright pink on the outside and the meat is opaque, 2 to 3 minutes.