Heat ¼ cup oil in an 8-qt. saucepan over medium-high heat. Add onions, and cook until caramelized, about 20 minutes. Transfer half the onions to a bowl; set aside for garnish. Add all beans, turmeric, and salt and pepper to onions in pan; cook, stirring, for 5 minutes. Add 12 cups water; bring to a boil. Reduce heat to medium-low; cook, covered, until beans are barely tender, about 50 minutes. Add spinach, parsley, lentils, and chives; cook for 20 minutes. Add noodles, and cook until noodles and beans are tender, about 12 minutes more.
Meanwhile, heat remaining oil in a 10" skillet over medium-high heat. Add garlic; cook until lightly browned and crisp, about 3 minutes. Using a slotted spoon, transfer to paper towels to drain. Return skillet to heat and add mint; cook until fragrant, about 1 minute. Ladle soup into bowls; top with reserved caramelized onions and garlic chips, then drizzle with the mint oil and whey.