when the result is unknown for a past counterfactual situation

We normally use the third conditional for describing past counterfactual situations. We use it when we’re sure about the occurrence or non-occurrence of both the condition and the result clause (more precisely, what is said in them). For example:

1. If she had studied, she would have passed the exam. (We do know that she didn’t study, and we do know that she didn’t pass the exam)

2. If I hadn’t eaten so much, I wouldn’t have felt sick. (I know I ate a lot, and I know I felt sick)

But there are contexts where a) we know about the occurrence/non-occurrence of the condition clause but do not know about the occurrence/non-occurrence of the result clause, b) we do not know about the occurrence/non-occurrence of the condition clause but we do know about the occurrence/non-occurrence of the result clause, c) we do not know about the occurrence/non-occurrence of the condition clause neither do we know about the occurrence/non-occurrence of the result clause.

Here, in this thread, I’m interested in situation(a) only. Consider the following, please:

Person A: My brother was supposed to appear for an interview at 8am, and now it’s 10. One of his friends called just a few minutes ago to inform me that he didn’t get the job, and I don’t know if he’s been sad for that.

3. If he had got(ten) the job, he would have been very happy.

4. If he had got(ten) the job, he would be very happy (right now).

Again, consider this, please:

Person A: My brother’s interview was at 10am, and now it’s 11. He left the house at 9:30am. I don’t know if he was on time for the interview or not. But, I’m sure

5. if he had left the house at nine, he would have been on time for the interview.

Another example:

Person A: My sister appeared for an exam a month ago, and I’m sure she’d not studied for the exam at all.

X: The exam results came out just an hour ago. I don’t know her results yet. But, I’m sure

6. If she had studied hard for the exam, she would have passed it.

Y: The exam results are not out yet. But, I’m sure

7. If she had studied hard for the exam, she would have passed it.

And I could go on and on.

Q: Are sentences (3), (4), (5), (6) and (7) correct?