Good appearance is subjective.
They will likely be judged against the standard of perfection for their individual breed, so it could be a beautiful (subjective) breed and score poorly for not meeting the standard, or score very well for being an outstanding example of a relatively plain breed.
Hatchery stock is hit or miss at best, but if 4-H is your end goal, it’s more about finding birds you will enjoy and learning from the experience. It will allow you to make the most of what you have.
One consideration though: White colored birds will require more grooming. Patterned birds will be more prone to pattern “flaws” so pick your poison.
I would prefer a quiet bird for new young poultry handlers, and one that is size appropriate.