/Ci ho fame/ always abbreviated with /c'ho fame/ is emphatic, and sometimes it needs to be said, just as its cousins: c'ho sete, c'ho caldo c'ho freddo c'ho voglia di un po` d'acqua Anything that relates to the condition of our body sometimes need to be stressed, especially in the spoken form, especially in children's talk (as it calls for urgent action). It is just an informal, but needed expression, nothing to do with dialects, it is pure Italian and pure expressions of our body.

It is true, but it is nonstandard expression in informal speech. However, It's possible, and allowed, to use "ci" (that becomes "ce" as you probably already know) with another pronoun with the aim to emphatize the sentence, for example: "Non hai mangiato nulla, non ce l'hai un po' di fame?" But you should avoid, mostly in writing, the forms "c'ho", "c'hai", c'ha"... and, if you can't, you should write them as "ci ho", "ci hai", "ci ha"... because, dropping the "i", the sound of "c" change from /Ч/ to /К/. Definitely, that kind of elision is out of the rules.

"c'ho fame" is a bit dialect, "ho fame" is exact italian and it's also more beautiful to hear. Italians use both, but it's better the second one :)