Are the sentences equivalent in meaning?

Every pair is equivalent in meaning.

In the last pair, say "She was a daughter of the President." I removed the 's. Also, is the person you are talking about dead? Because talking about her in past tense suggests that she is deceased. If she is living, but her father's time in office has ended, you can avoid confusion by saying which President. "She is one of President George W Bush's daughters." or "She is a daughter of the former President."

All the other sentences are correct, I believe. In the 2nd, 3rd, and 4th pair, the second sentence sounds more natural.

They are both grammatically correct and mean the same thing but they may sound very strange to native speakers.

In example one (Susan) both are often used but the "friend of" form would only be used when introducing yourself to someone.

In example 2, "Maria's brothers" would more likely be used as a brother is a person.

In example 3 both may be used.

In example 4, the difference is in the tone; "daughter of the president" has much more gravity than the other sentence.