Without seeing the back, it looks like maybe just a pied, maybe pearl pied. It's hard to tell Cinnamon through pictures for me. Posture wise, I say yours is female.
It's hard to tell male from female with certain mutations. Most mutations the females will have barring on the underside of their tail feathers. You can tell, behavior-wise as well, but this is much harder. Most females do not mimic except for certain sounds. My female mimics kisses. So, It does happen, but not often. Males can, and do, mimic human speech, though it is no where near what a Macaw can do or even an African Grey. Males are your whistlers, your mimickers(sp). They come up with ornate, elaborate whistles and will charm the pants off you. Females, in my experience, are the snugglers, cuddlers and are more apt for soft coos versus lengthy conversation.
Most Tiels love millet. I usually have a spray or two in their cages at all times. It's a treat. Mine both have Cuttlebones. My male prefers the Raspberry Flavored, my female likes plain. Common practice nowadays is to feed pellets, and Roudybush, when I feed it, is preferred by my two. I am old school. I feed seed. My male is 13, and my female will be 3. Giving other foods takes time with them. Mine generally will refuse to eat anything that I didn't introduce to them when they were still really little. They hate virtually all fresh veggies. My male loves coconut, raspberry (dehydrated), cabbage (dehydrated), carrots (dehydrated). My female loves nuts, papaya (dehydrated). Neither will touch the dried peas, bannanas, or raisins in their food. As long as you are feeding a well balanced food, with a variety, IMHO a seed based diet is fine. Keep in mind, seeds are fattening so exercise is needed.
They are usually recommended as first time birds. They are even keel, personable, and friendly. They are a softer parrot and it is not generally in the birds makeup to make a racus. Unwanted behaviors like screaming are somewhat rare. I just happen to have one learn the behavior over the years and its a bear getting him to unlearn it.
Tiels, from what I heard, like cages that are wider than they are tall. But, mine are both in cages that are taller than they are wide and are both fine. The bar spacing should be less than 1/2". They can do with a smaller cage if they are rarely in it. Toys, my birds prefer shreddable toys, though the kind they like are completely different. My male likes the stuff Chinese finger traps are made out of, and my female likes toys that mimic preening that can also be shredded. They both enjoy paper products. Stay away from mirrors and hanging toys that they can get trapped on or in. Avoid mirrors or reflective services.
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