Limbs of wudhu shining with radiance

Q: In these Ahaadith:

Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah sal Allahu alayhi wa sallam went to the (Baqi`) cemetery and said, “May you be secured from punishment, O dwellers of abode of the believers! We, if Allah wills, will follow you. I wish we see my brothers.” The Companions said, “O Messenger of Allah! Are not we your brothers?” He said, “You are my Companions, but my brothers are those who have not come into the world yet.” They said; “O Messenger of Allah! How will you recognize those of your Ummah who are not born yet?” He said, “Say, if a man has white-footed horses with white foreheads among horses which are pure black, will he not recognize his own horses?” They said; “Certainly, O Messenger of Allah!” He said, “They (my followers) will come with bright faces and white limbs because of Wudu’; and I will arrive at the Haud (Al-Kauthar) ahead of them.” [Muslim]

and this: “On the Day of Resurrection, my followers (or Ummah) will be summoned ‘Al-Ghurr Al-Muhajjalun‘ from the traces of Wudu’.” [Al-Bukhari and Muslim]

In these hadith, it says limbs will be shining white on the day of judgement. In an earlier hadith, you say that people will be white in complexion in jannah? I was wondering, does this mean people will be white in complexion on the day of judgement or just simply shine due to the light?

Making qadha due to eating sehri after fajr time sets in

Q: On the first day of Ramadhaan I did not know about the 18 degrees fajr time so I ate suhoor after fajr entered according to 18 degrees fajr time. After the first day I found out about the 18 degrees fajr time and how its more accurate than 15 degrees so I started following that after the first day. Regarding that first day, since I did not know about the 18 degrees fajr time, do I have to make it up? And do I have to make it up immediately after Ramadhaan or any time up until the next Ramadhaan?

Surnames

Q: Are Muslim women allowed to have male names like Khan, Ali, Hussain, Mohammed, and Hassan. Some Muslim Imams say that females are not allowed to have male names.

Halaala

Q: As per law of Shariah, divorce happened between me and my husband as he said talaaq thrice. Now he wants me back. What is the proper way of halaala?