Is a girl who wishes to wear the niqab and is convinced of its obligatory nature required to obey her parents, who strongly reject the niqab, especially given that the father is not religiously committed, and does the hadith "There is no obedience to a created being if it involves disobedience to the Creator" apply to this situation?

There is no obedience to parents if they command the abandonment of the niqab. It is obligatory for the woman to adhere to the niqab, and you should not obey your father in preventing you from it, for no one is to be obeyed in disobedience to Allah. However, if you fear falling into severe hardship, there is no harm in seeking a concession and acting upon the opinion of those who do not deem it obligatory. Indeed, it may be permissible for an ignorant person to follow a scholarly opinion and to take a concession from the sayings of scholars at certain times when there is a pressing need, without habitually seeking out concessions. This is what makes اختلاف (disagreement) a mercy, for concessions are a mercy. In this situation, strive not to leave your home except out of necessity. We advise supplicating for this father’s guidance, and he should be advised with gentleness and kindness, especially concerning Fajr prayer and congregational prayer.