Clothing and Covering the Aurah

Q: Is salaah acceptable if the trouser of a man is going very low from the back but the line between the buttocks is not visible?

Q: Is topi (head covering) for men is necessary in salaah?

Q: I want to know if a man's trouser is minorly torn at different places, can he perform prayers or do dua?

Q: I've prayed Salaah with a garment on many occassions and just recently discovered a hole in it slightly above the knees. Since the male awra is above the knees does that mean all of those prayers were invalid, and do I have to make them up? Also do skinny jeans invalidate salah since they show the shape of the legs?

Q: Is namaaz valid in half sleeve shirt?

Q: Can we offer Salaah wearing a T-shirt with the British flag or any other country's flag printed on it?

Q: Is it permisble to perform salaah wearing skinny jeans/ leggings/ tight fitting clothes?

Q: My hairs are long and silky. When I perform Salaah, my hat falls off in sadja. Is it necessary to wear a hat in namaz or can I put on another thing to cover my head?

Q: Can we offer Salaah in half sleeve shirt?

Q: Please advise if men can wear shorts under the kurta and read Salaah with it even if it is a bermuda and covers the satr till below the knees in. If so, is there a specific length that it needs to be?