Answer:
(Fatwa: 2511/321=B/1429)
(1) Yes, it can be offered, but it not better.
(2) Yes, it can be offered except after Fajr and Zuhr prayers.
(3) It is not necessary; he may go or may recite dua and Ayatul Kursi as per his wishes.
(4) It is desirable (mustahab) not necessary, one should leave it occasionally.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
