Answer:
(Fatwa: 1942/1723=B/1429)
(1) The front part of the neck should not be open when one wears the scarf, but according to your writing if the front part of the neck is open while salah then also salah will be valid, there will be no qaza. However, if one fourth part of the neck or more than it is open then salah will not be valid.
(2) Salah will be valid, but it is undesirable for women to wear such transparent clothes.
(3) Salah will not be valid if one fourth part of the head is open. Salah will be valid if only some hair-locks are seen.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
