I have been told that Qurbani is not required for children even if one has the affordability. Is this accurate?
Can one also do Qurbani for members of family who have passed-on?
1. The correct opinion upon which Fatwa is given in the Hanafi Mazhab is that Udhiya (Qurbani) is not waajib upon a non-baaligh (child) nor is it waajib on his behalf upon the child's father or guardian. This is in Bahare Shariat with reference to al-Durr al-Mukhtar. If, however, one wishes to do Qurbani on behalf of the non-baaligh children then there is no harm but rather reward and Allah knows best.
2. It is rewarding to do Qurbani on behalf of those who have passed away. Imam Tirmizi has recorded in his Jaami' and Sunan that Sayyiduna Ali Radi Allahu Anhu would do Qurbani on behalf of the Messenger of Allah ﷺ. If the deceased requested that Qurbani be done on his or her behalf then the meat must be given to the poor and if not then it can be eaten by themselves and whoever they wish to give it to and Allah knows best.