Clothing and Covering the Aurah

Q: Is a woman allowed to perform salaah with her niqaab covering her face in the presence of non-mahram men?

Q:

1. I now wear 2 khimars, 2 shalwars, 1 half-sleeve T-shirt underneath two kurtas, and a pair of gloves (and I try my best to tuck in the sleeves of the 2 kurtas into them) until the wrists because my clothes are thin and quite see-through. After wearing these clothes, I feel comfortable, Alhamdulillah, that the satr is not going to be seen.

My question now is that if a woman goes into sajdah and if she is wearing a see-through kurta (and no other shirt) and even though her khimar (which reaches almost until her knee cap when she is standing) still covers her body during sajdah by draping around it but does not cover the kurta itself such that if someone (like an angel or a jinn) were to watch her from below the ground, they would see the kurta uncovered by the khimar but someone standing on the ground could not see anything underneath the khimar at all. Does this invalidate the prayer?

2. If two limbs are exposed during Salaah, each less than a quarter of its whole area, how can a woman know if it invalidated her prayer? What is the length she can measure to?

3. If a woman wears shalwar (which kind of shows her figure but is not figure-hugging like tights), then is her Namaz valid?

Q: Will a woman be allowed to wear a long dress or long skirt to read salaah?

Q: Can I pray in leggings if my top ends a few inches above my ankles?

Q: Is not covering the feet below the ankles for woman against sunnah? I have severe waswasa and I found out that except for Hanafi's, others consider the feet as awrah. Are my prayers invalid as I didn't cover it after knowing about the ruling. Why do Hanafi's not consider the feet as awrah. I feel scared that my namaz isn't valid. What should I do?

Q: Is salaah valid when one is performing salaah individually at home while wearing pyjamas or other night attire?

Q: Does the area starting from the chin need to be covered during salaah for women?

Q: If the dress or skirt of a Hanafi woman is above her ankles (i.e. the ankles and part of her shin are exposed), will her salaah be valid if she prays salaah after putting on socks to cover the exposed area?

Q: Is it mandatory or necessary for women to wear something under the gown (like to wear a shalwar or pants under a night dress) in order to perform namaaz or can she read her namaaz just wearing the gown or night dress which covers the whole body up to the feet but nothing inside. Will her namaaz be valid?

Q: If a person prays while wearing a t-shirt that has depictions of creatures on it, is his prayer valid or should he repeat it?