Is it permissible to delay the aqiqah to coincide with Eid al-Adha, and if the price of the calf is high, is it permissible to make part of it an udhiyah, and should this aqiqah be divided into three parts or be treated like a vow?

Whoever vows an act of obedience must fulfill it and not change it. If you vowed to sacrifice a calf, you must sacrifice it if it has reached two years of age. The vow must be fulfilled as it was vowed. Allah, the Almighty, says: "They fulfill [their] vows and fear a Day whose evil will be widespread." The basic principle for udhiyah (sacrificial animal for Eid al-Adha) and aqiqah (sacrificial animal for a newborn) is to eat from them, give as gifts, and give in charity. However, if the one who vows specifies a recipient for the vow, it must be given to them, and the one who vowed may not eat from it.

The time for aqiqah is on the seventh day. If not possible, then on the fourteenth, or the twenty-first. As for the time for udhiyah, it is well-known, and it is not permissible to offer it before its due time. Scholars differed on the permissibility of combining the intention of udhiyah and aqiqah in one animal; the Hanbalis permitted it, while the Malikis and Shafi'is prohibited it due to the difference in their objectives. Udhiyah is a redemption for oneself, and aqiqah is a redemption for the newborn.