Is it correct to release the state of Ihram before the Miqat and then enter into Ihram from Medina, and does this entail a دم (sacrificial offering) for the wife and her mother, and what is the ruling regarding the husband?

Whoever assumes the state of ihram for a ritual must complete it, and it is not permissible to abandon it. Assuming ihram before the miqat is valid, based on the Almighty's saying: "And complete the Hajj and 'Umrah for Allah." What you did by instructing your wife and her mother to cancel the 'Umrah was an error. It was obligatory to ask before proceeding to annul the ihram, based on the Almighty's saying: "So ask the people of the message if you do not know," and the Prophet (peace be upon him) said: "Why did they not ask if they did not know? Indeed, the cure for ignorance is asking."

Their rejection of the ihram is not valid by scholarly consensus. Therefore, any prohibited acts of luxury they committed (such as wearing sewn clothes, applying perfume, or engaging in sexual intercourse) incur no penalty upon them due to ignorance. As for acts involving destruction (such as shaving and cutting nails), for each of them, for each type of prohibited act, there is a fidyah: fasting three days, or feeding six needy persons, or sacrificing a sheep. They have a choice among these options. If the prohibited act was repeated, they are only required to offer one fidyah. What you did by sacrificing on their behalf is good, but they might owe more than one fidyah depending on the prohibited acts they committed. Therefore, you must ask them about the number of prohibited acts and then offer a fidyah for each prohibited act. As for you, you owe a dam (sacrifice) for passing the miqat without ihram, and your dam is not waived by the fact that you assumed ihram from Abyar Ali.