These two are correct: We are only a few days away from the deadline. The deadline is only a few days away. The other two sentences could be understood but are not usually used. I hope that helps!

Thank you Dianez. It's very helpful.

All of them are correct except, "We are only a few days off the deadline" doesn't really work on it's own because it's vague. Someone would need to know what is going on. It is not correct if someone is trying to meet a deadline that is in the future. "Away" refers to future. "Off" can refer to the past. If someone is off their deadline, they are late! For example: Person A: "The supplies are arriving late. How many days are we off our deadline? Person B: "We are only a few days off OUR deadline". "Deadline" is in the part of the sentence that acts like a prepositional phrase. The sentence is "We are only a few days off". That is a complete sentence. So, just saying "the deadline" is basically an incomplete prepositional phrase. You could say, "We are only a few days off FROM MEETING (your, our, his, her, their, my) deadline." Still, the sentence is reliant on previous sentence.