Yes, none in english reffers to an object in most cases and no one or nobody is like none, but for people. For example, she has none. Or in a conversation between 2 people Person 1: "Nobody has one in this room?! There's not even one?!" Person 2: "Yup. There are none in this room."
Yes, but nouns usually change with the article "Die, der, das" and "ein, eine". "Es" doesn't have an article.
I found this discussion: http://german.stackexchange.com/questions/15111/keiner-jeder-vs-niemand-alle
They're interchangeable in daily speech, but niemand means "nobody (at all, anywhere, ever)" and keiner means "nobody (in this group)".
German and English are very similar. Old English was just pretty much just German, until the French began interacting with England more, and it became Middle English, which is like Modern English, except words ended with "e" a lot, "eth" was used instead of "ed" for verbs, and they used words we didn't, like "thy" and "thou".