5. How was Abu-I-Aas freed from the captivity of prisoners?

A.  As discussed earlier that except Abu-I-Aas, all the members of the family of Prophet sallal lahu alaihi wasallam embraced Islam.
 Quraysh then did not want there sons to to remain married to the daughters pf Muhammad sallal lahu alihi wasallam because of there
 animosity.  They came to Abu-i-Aas and asked him to divorce his wife, promosing him to give any woman of there community in his marriage.
But he replied that he won;t divorce his wife as he wishes to have no other woman in the place of Zaynab RA.
Here other two daughters of our Prophet SAWS, Ruqqayah and Umm Kulthum, returned as divorced by there husbands. The Prophet SAWS was indeed delighted  when they came back and hoped Zaynab RA too to return to him as he had no power to compel him to do so. The law forbidding the marriage of a Muslim woman to a non believing man was not yet in force.

After few years Prophet SAWS along with other believers migrated to Madinah. Quraysh fely even more threatened by him, so confronted
him ay Badr. Here they forced Abu-i-Aas to join them. Though Abu-i-Aas did not wish to but had to go with them. Here i need to remind a point that this sahaba then did not embrace islam not because of any hatred towards islam but for the only reason that he did not want to leave his religion of forefathers. Anyways, while battle of Badr , Quraysh faced terrible defeat and few managed to escape while others  were taken as prisoners.Amongst these prisoners were Abu-I-Aas.
 
The Prophet SAWS fixed amounts for the ransom of priosoners according to there wealth and social standing. Quraysh messengers were moving to and fro from Mecca to Madinah bearing ransom money to free there relatives and others.
Zaynab RA sent her messenger to Madinah bearing the ransom demand to free her husband. The ransom amount included a necklace which her mother Khadijah RA had gifted her during her marriage. When Prophet SAWS, saw the neckalce, his face at once became covered with a veil of sadness.and he felt a surge of tendrness for his daughter. He turned to his companions and said .
" Zaynab has sent this amount to ransom  Abu-I-Aas. If you see fit to set freee her prisoner and return her possessions to her, then do so"

"Yes,",  his companions agreed. "We shall do whatever we can to soothe your eyes and make you happy"

The Prophet SAWS set one condition on Abu-i-Aas before he freed him, that he shud send his daughter Zaynab to him without delay"

Thus he was freed. Abu-I-Aas tried his best to carry his promise but after alot of hindrances though late, he fulfilled his promise. His story of embracing Islam shall be discussed later insha-allah. 
This incident shows us that Islam is not a religion where in enemies are forced to embrace islam. Secondly, prisoners were not ill treated, instead they were freed with a ransom amount taht too was fixed affordable according to the social status of a prisoner. There were tears in the eyes of our Prophet SAWS when he saw the Necklace of Khadijah RA and felt the tenderness of his daughter too. This shows us that a prophet is a human being and thus has emotions as we. Few people state prophet as "noor of Allah", or else.

Next set of Questions:

1. Where and why does Qur'an speak of Habil and Qabil? i dont know where. but i know that these were the sons of Adam AS and that one killed the other and didnt know how to dispose of his body. then a raven came and showed him how to bury the body.

2. Which nation considered itself to be the strongest on the earth?

3. What were the special blessings and favours over Sulaiman AS?. he could speak to and understand the animals. he could control the winds or something like that.

4. Who was brother of Musa {AS]  Haroon

5,Apart from Umar RA, who was the other option Prophet SAWS wished to embrace islam?

Jazakallah Rookaiya and Taliyya for your answers. Both of you were near but not exact at few answers. Answers which need explanation are been discussed . Once again i thank u for ur intrest and wish u all to keep answering them.

2. Which nation considered itself to be the strongest on the earth?

Its the nation of Ad. Allah ta'ala mentioned their story in the Qur'an in more than one place, so that the believers may learn a lesson from their demise.  Surah Fajr says :
(As for 'Ad, they were arrogant in the land without right, and they said: "Who is mightier than us in strength'' See they not that Allah Who created them was mightier in strength than them.)
(The like of which were not created in the land) meaning, there had been none created like them in their land, due to their strength, power and their great physical stature.. They were the strongest people of their time in their physical stature, and they were the mightiest people in power. Thus, Hud reminded them of this blessing, and he directed them to use this power in the obedience of their Lord Who had created them. But they were arrogant of this blessings of Allah.

4. Who was brother of Musa {AS]

Here are few verses which tell of Musa AS  and his Brother Harun.
Musa said: My Lord! I have killed a man among them and I fear that they will kill me And my brother Harun -- he is more eloquent in speech than me : so send him with me as a helper .When Musa asked for this, Allah said to him: We will strengthen your arm through your brother.And other verses  in the Qur'an says :

 And We granted him his brother Harun, (also) a Prophet, out of Our mercy (19:53)

. ("And loose the knot (the defect) from my tongue. That they understand my speech.And appoint for me a helper from my family, Harun, my brother. Increase my strength with him, And let him share my task

(Salam (peace!) be upon Musa and Harun! Verily, thus do We reward the doers of good. Verily, they were two of Our believing servants.)