I have a Kaffarah (expiation) on my conscience, and I know that the expiation, in terms of feeding, is to…

I have a Kaffarah (expiation) on my conscience, and I know that the expiation, in terms of feeding, is to feed ten poor people. I have three inquiries: 1- What is the amount of food to be given to each poor person (in kilograms), considering that rice or flour is available? 2- Is it permissible to give the food to someone (a Sunni follower) to distribute it to the poor? They have knowledge of the needy and deserving individuals, as I don't know any poor people, and we live in a community that is not Shia, making it difficult to find Shia scholars or those who can distribute to the poor. 3- Regarding breaking a pledge with Allah, as I made a vow to Allah to refrain from something and I broke it. I seek repentance and forgiveness. Is there an expiation for this, and what is its form?