Heat the oil in an 8-quart pot over low-medium heat. Add the onion, carrots, celery, potatoes, squash, sage, thyme, fennel seeds, salt, and pepper. Stir to coat. Cover and cook for 15 minutes, stirring occasionally. Add the pepperoni, tempeh, and water. Raise the heat to medium-high and bring to a boil, stirring occasionally. Cook at a medium boil for 30 minutes, stirring occasionally until the carrots are tender. Add the cabbage, hot dogs, and sauerkraut. Cover and cook for 5 minutes, then stir and continue cooking, covered for about 10 minutes, until the cabbage is tender. Taste for seasonings.