salam!
here are a few of the hadiths i got abt niqaab and hijaab! i hope they are of help!
The wives of the Prophet sws used to go to Al-Manasi, a vast open place (near Baqia at Medina) to answer the call of nature at night. 'Umar used to say to the Prophet "Let your wives be veiled," but Allah's Apostle did not do so. One night Sauda bint Zam'a the wife of the Prophet sws went out at 'Isha' time and she was a tall lady. 'Umar addressed her and said, "I have recognized you, O Sauda." He said so, as he desired eagerly that the verses of Al-Hijab (the observing of veils by the Muslim women) may be revealed. So Allah revealed the verses of "Al-Hijab" (A complete body cover excluding the eyes).
The Noble Qur'an - Al-Ahzab 33:59
O Prophet sws! Tell your wives and your daughters and the women of the believers to draw their cloaks (veils)* all over their bodies (i.e. screen themselves completely except the eyes or one eye to see the way). That will be better, that they should be known (as free respectable women) so as not to be annoyed. And Allah is Ever Oft-Forgiving, Most Merciful.
*the arabic word here is Jalabeeb (plural of Jalbaab), which is the loose outer garment that covers all a woman's body. It says here to use the Jalabeeb to cover all, and scholars say this means to use it to cover her head (agree upon by all scholars) and her face (agreed by many scholars, not all) and one or both eyes, in order for it to be known that she is a free woman and so not to be exposed to any harm.
Hadith - Bukhari 6:282
'Aisha used to say: "When (the Verse): 'They should draw their veils over their necks and bosoms,' was revealed, (the ladies) cut their waist sheets at the edges and covered their faces with the cut pieces."
Hadith - Abu Dawud, Narrated Umm Salamah, Ummul Mu'minin
When the verse "That they should cast their outer garments over their persons" was revealed, the women of Ansar came out as if they had crows over their heads by wearing outer garments.
The lower half of the hijab is a garment that does not show the woman's figure. Jeans and certain obvious garments do not meet this requirement.
Hadith - Abu Dawud, Narrated Dihyah ibn Khalifah al-Kalbi
The Apostle of Allah was brought some pieces of fine Egyptian linen and he gave me one and said: Divide it into two; cut one of the pieces into a shirt and give the other to your wife for veil. Then when he turned away, he said: And order your wife to wear a garment below it and not show her figure.
ma'salamah