Thanks everyone!
I went to several pet stores today looking for something great and in the end I bought some basic cockatiel mix from Pet Supplies Plus - contains millet, oat groats, dried egg food, some kind of bean, that kind of stuff(from the bulk bin), added safflower seed to it, some sunflower seed, dried banana, dried papaya, raisins, and basically made my own mix.
They do eat cooked broccoli, peas, orange, cherries, apples, cooked egg, cooked pasta, mozzarella cheese. I am struggling a bit with Harrison's pellets, but we'll keep trying.
Hopefully, they are getting some nutrients.
Oh, and Remi absolutely loves cooked grits, cream of wheat, granola and rice bits cereal (unsweetened). Petey is more picky.