Who is Ruqayyah. Is she another daughter of Imam Husayn besides Sukayna? How many of imam Husayn's children survived Karbala besides Imam Zaynal Abedin a.s?

Even though many historians have not made mention of a small girl of Imam Hussein with the name of Ruqayyahh, Fatimah Sughraa or any other name in their books, but some books do cite the story of this small girl and the tragic incidents that took place for her in the ruins of Sham (current day Syria).
There are also clues in our hadith and history sources that support her existence and we will mention a few as examples:
First: When Lady Zeynab was speaking to the head of her brother, Imam Hussein, she recited poems that consisted of the following sentence: "O Brother! Speak to little Fatimah for it is close for her heart to become empty (it is close for her to pass away)."
Second: When encountering Shimr at the final moments of his life, Imam Hussein states: "O my Zeynab! O my Sukainah! O My children! Who will be your guardian after me? O my Ruqayyahh! O my Umme Kulthoom! You are Allah's trust. Today we have come close to the promised moment."
Shiekh Mufid says: "Sukainah is among the daughters of Imam Hussein and her mother's name is Rubab."
Sheikh Tabarsi says: "Sukainah, the daughter of Imam Hussein, was ten years old on the day of Ashura."
Therefore, many books have mentioned Sukainah as one of Imam Hussein's daughters.
It is understood from these ahadith that the Imam had another daughter also named Sukainah who at that time- before the incident of Karbala-had reached the age of marriage.
Taking what was said into consideration, one can conclude that a daughter of Imam Hussein (who was either named Ruqayyahh or Fatimah) passed away beside the head of her father in the ruins of Sham, and that this little girl was not Sukainah, the other daughter of the Imam who lived for many years after her father's martyrdom.