Can 自分replace 私 completley? how do you use Jibun to refer to other people?

Question

Answer

I don't thing they are interchangeable. "Jibun" refers to the TOPIC of the sentence. That could be "me", "you", or just about anything. 
彼、自分の車を使う。= he uses his own car.
自分の車ですか？ = is that your own car?

Answer

Basically they are exchangeable with each other. Of course, there are some exceptions. Could you give my some situations you are considering so that I can give you more specific answers. 
I don't understand the meaning of the second question. Do you want to know how to say you in japanese? Then, the answer is anata.

Answer

ほんとうーにありがとう、みなーさん！！＾＾

Answer

I guess not, it means my, or myself(oneself,him/her/on -seself.
While watashi is I

Đừng bỏ lỡ cơ hội học ngoại ngữ ngay tại nhà. Hãy xem danh sách các gia sư ngôn ngữ giàu kinh nghiệm của chúng tôi và đăng ký buổi học đầu tiên ngay hôm nay!