Is it permissible to prioritize Hajj over repaying debts, and what is the ruling if the creditors allow a deferment of payment? And is assisting one's wife after childbirth considered a valid excuse to postpone the obligatory Hajj, especially if the birth occurred a week before Hajj and there are no mahrams for the wife in the country?

If the debt is due and the debtor does not possess the means to perform Hajj after repaying it, then the debt takes precedence over Hajj, even if it is an obligatory Hajj. This is based on the Almighty's saying: "And Hajj (pilgrimage to Makkah) to the House (Ka’bah) is a duty that mankind owes to Allah, those who can afford the expenses (for one’s conveyance and provision for himself and his family) for it." [Quran 3:97]. The debtor, in this case, is not able. However, if the creditor grants permission, or if the debt is not due, then there is no harm in performing Hajj. Assisting one's wife after childbirth is not an excuse to delay the obligatory Hajj, unless the husband's presence is essential for her assistance, in which case he is permitted to delay it.