Sunnah & Nafl Fasts

Q: Is there any special virtue established for fasting during the month of Muharram?

Q: Outside Ramadhaan, one frequently fasts but one’s object is really to try and get sugar levels down. Would such fasts be deemed nawaafil fasts or merely regarded as a personal exercise not deserving of any reward?

Q: The shawaal fasts, should they be observed directly after Eid day or can one fast any of the 7 days during the month of shawaal?

Q: Whenever the 13th, 14th and 15th of the month comes, my niece gets her menstrual cycle, so she is not able to fast during those days. So should she keep those fasts after her menstrual cycle or just leave it because she can't do it?

Q: When we go for Haj should we fast on the day of Arafah?

Q: Is it permissible to make an intention of Qadha for fasts that were missed in Ramadhan and also for the 6 Sunnah fasts of Shawwal? I heard that to get the reward promised in the Hadith you will have to keep 36 fasts (Ramadhaan plus 6 fasts of Shawwaal). Is this correct?

Q: What are the forbidden days to fast in the Islamic calender/ year? Also which are the favourable days to fast in the months and year.

Q: There is only one week remaining of Shawaal, and I want to keep the six fasts of Shawaal. However, I have 13 qadha fasts to keep. Should I keep the qadha fasts first and miss the six fasts of Shawaal or can I keep the six fasts first and thereafter make up the qadha fasts? 

Q: What is the significance of fasting for two days?

Q: Besides the Monday and Thursday fast, what are some other days that one should keep Nafl Fast? I have heard people say that one should fast on Ashura, and 15th of Shaban (Shab-E-Baraat), and on the birthday of Rasulullah (Sallallahu Alayhi Wasallam)? Are any of these correct or should these be avoided?