Circumcision for a revert adult Muslim

Q: I wanted to ask for some guidance regarding circumcision for a revert. 

Is it fardh for an adult revert to undergo circumcision, or is it considered sunnah? I am particularly concerned about the medical risks involved, such as possible infection and bleeding, especially as an adult. 

How should someone in this situation approach the matter, balancing religious obligations with health considerations? Are there circumstances where it can be delayed or excused?

Marrying one's milk sister

Q: I wanted to marry a girl but later they told me that her mother breastfed me once when I was less than one year. I researched about it and according to my knowledge in Quran it is forbidden to marry but there is no evidence of how many times of breastfeeding is required. From hadith I found that there is one hadith from Hazrat Aaisha (radhiyallahu anha) which states that five breastfeeding is required to make it haram. Please guide me regarding this issue.

Children standing in the adults' saffs if they are misbehaving

Q: Is it correct for a person to keep his sons behind him in the masjid - away from other children as these children are causing a disturbance in the back. Some children hit others. 

What will be the correct age to bring children to the masjid? Any guidelines regarding the children's saffs as some mention that the children can stand in the adults' saffs if they are misbehaving. 

Please clarify with guidelines for our masaajid.

Males using skin care products

Q: For beautification purposes, for a man,

1. Is it permissible for him to try to make his eyebrows thicker by stimulating the hair using oils or serums, or by massaging the area to improve circulation? 

2. Is it permissible for him to try to remove skin tags, warts, acne, or abnormal looking moles from the skin by the means of skincare? 

3. Is it permissible for him to try to remove his under eye bags using vitamin serums or other types of serums, and their diet? 

4. Is it permissible for him to try to remove his tan using skincare and diet, or try to get tanned using sun bath?

Postponing hajj due to the fitnahs in the haramain

Q: There is a lot of fitnah happening in Saudi Arabia; the government is allowing a lot of haraam there. The Hajj is being used by the government to extort money from Muslims. Muslims are committing a lot of haraam near the Kaaba; there are reports of men touching women's buttocks during the circumambulation of the Kaaba. Many are taking photos inside the Hajj to the point where it's almost impossible to avoid being recorded. 

Would it be permissible to postpone the Fard Hajj until things improve in Saudi Arabia, thus allowing for a purer Hajj without involving haram?