1. Is it yours to give ?
Is it for you to give ?
2. It is not mine to give.
It is not for me to give.
Of these sentences, which are correct ?
The "for+subject+to" is used in grammar books, but the other constructions with the possessives is quite common especially in these into sentences.
Debpriya Deother constructions with the possessives
Think of these constructions as special idioms. They occur after linking verbs.

It is (not) -- [mine/yours/his] to give.

The "normal" use spoken of in your grammar books is most likely the for ... to ... constructions that occur after certain adjectives and verbs.

It is important for you to be here on time.
I am waiting for him to answer my question.

Both sentences are correct.

It is not mine to give. = I don't own this thing, so I can't give it to anyone. (refers to physical objects)

It is not for me to give. = It's not my job or responsibility to give things like advice or direction to someone. (refers to nonphysical things and is similar to ''It's not up to me to give.'')
It is not (for me)(up to me) to give your son that kind of advice.

The first set of sentences, the questions, are comparable in meaning to the above.
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 CalifJim's reply was promoted to an answer.
"It is important for you to be here on time."

This is a cleft sentence, but my original sentence was not meant as a cleft sentence.
It was like "That is not for me to give", except I used "it" instead of "that".
Even the other sentence was meant to be like "That is not mine to give". The "it" was not an anticipatory "it".
Debpriya DeThis is a cleft sentence
The sentence contains anticipatory "it", but it is not a cleft sentence. Cleft sentences are of the form

It is [ ] that ... as in It is [the key to the front door] that I lost.

The highlighted element (within [ ] ) is most often a noun phrase.

I am also aware that the "it" in your example was not an anticipatory "it".

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