Short answers, pulled from the story.
Excommunication functions as an institutional act used to deprive or limit membership within a religious community. It serves to exclude those whose behaviors or teachings contradict the core beliefs of a Christian community.
Pope Leo X issued the papal bull Exsurge Domine on the 16th of May 1520, condemning Martin Luther's propositions regarding church authority. This document declared that excommunications are not merely external punishments but spiritual penalties binding in heaven.
The Church of Jesus Christ of Jesus Christ of Latter-day Saints ceased using the term excommunication in 2020 replacing it with withdrawal of membership. Formal membership councils now emphasize the availability of repentance rather than focusing on guilt while stake presidencies and high councils decide whether to withdraw the membership of Melchizedek priesthood holders.
Disfellowshipping severs friendly relationships between all Witnesses and the disfellowshipped person restricting interaction even with extended family to minimum levels like reading wills or providing essential care for the elderly. Reinstatement requires applying in writing to elders who determine if sufficient time has passed for genuine repentance to be proven.
In South Asia Hindu caste councils historically practiced excommunication resulting in abasement of caste status or throwing individuals into the sphere of untouchables. The Gupti Ismailis from the Hindu Kachhiya caste were excommunicated completely in the early 1930s after conflict over allegiance to the Ismaili Imam.