I would eliminate the charcoal. And make sure you have some sort of calcium- crushed egg shell and cuttlebone (stay away from grit or sea shell if you can).
But the ratios are important: 50% seed, 20% sprouted seed, 20% fresh produce, 10% additives (egg food, etc)
(I often give a larger percentage sprouted seed)
Make sure you also give a supplement which contains trace minerals and vitamin D3. But they can eat just about anything- they can sometimes be a little timid of new foods. But I have made bird bread type things for them, fresh fruit occasionally and of course live food. Meal worms, etc.
The most valuable of the produce items are Apricots, Mustard Greens, Kale, Collard greens, Baby lettuce mix (not romaine), Carrots, Peppers, Zucchini, Turnip tops, and Herbs. I also give what I call 'Herbal Tonic' it is a mixture of herbs that does amazing things for the birds, reducing illness, increasing feather density and generally makes them calmer (healthy birds are happy birds).