Permissible and Impermissible actions in Ihraam

Q: I heard that people don't wear underwear in Hajj. Is that true?

Q: I am planning to go for Hajj in 2020 but not sure what kind of sandal I can wear when I am in ihraam. I found that some of them are saying I have to wear a slipper with the 2 belts (flip flop) without any stitches. Some say that I can wear any kind as long as the back and the front are open and some say that it cannot cover the middle part of the foot. Please  explain to me what kind of footwear I can wear, if possible a picture would be great.

Q:

1. Can I wear sunglasses when making tawaaf for umrah and hajj? 

2. Can I wear perfume at the time of tawaaf for umrah and hajj?

Q: I would like to know what kind of slipper I can wear in the state of ihraam. Is it a must to wear a 2 belt slipper or I can wear the slipper which is open in the front and back?

Q: Can a patient who has a urine problem perform umrah by wearing a pamper (diaper) in tawaaf?

Q: If one wishes to wear a clean ihram while in the state of ihram, is the new ihram permitted to have a scent like a normal soap scent? Can one prepare ones second ihram with perfume?

Q: Is it permissible for a person in the state of ihraam to apply ointment for pain? The reason I am asking is that all ointments generally have a scent, whereas all scented things are prohibited in the state of ihraam. 

Q: I intend going for umrah. Due to my leg problem, I need to wear a compression sock. The compression sock covers the entire leg. Is it permissible for me to use this sock while in ihraam? 

Q: If one goes for umrah or hajj, and during the journey, his ihraam clothing becomes soiled, can he change into a clean ihraam, or is it necessary for him to continue using the same ihraam while merely washing the soiled area? 

Q: I have a problem of urine drops after urine and also upon waking up. Is it permissible to tie a tissue for example with an elastic band for istibra purposes then remove, and also to have a tissue tied under ihraam during sleeping to prevent ihram from being affected with the drops during sleep