In Umrah and Hajj how could pilgrims release each other from their ritual state (Ihram)? Can they cut the hair for each other or do they need young boys with scissors to do it for them for a donation?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The person who is in the state of Ihram (i.e. before the time of Tahallul: freedom to take off Ihram or leave it) should not take any of his hair without a sound excuse. Similarly, it is not lawful for anybody else to take out any of the hair of a person who is in the state of Ihram. When the time of Tahallul comes and this person wants to shave his hair, he can let another person in a state of Ihram do it for him and neither the shaver nor the person who has his hair cut are blamed for that, because this hair is now similar to the hair of any beast and can then be destroyed without being in contradiction with Islamic rules. This is the soundest opinion of scholars. It is also the opinion of Shafi'e and Hambali Madhab (school of thought).
Some scholars, however, believe that if the person in a state of Ihram shaves the hair of a person who is not in a state of Ihram, the former has to give a Sadaqa (alms). This is the Madhab of Hanafi School of Thought. Imam Malik said that the Mohrim (person in the state of Ihram) gives a Fidya (a sort of ransom) if he shaves the hair of a non-Mohrim. So for the Hanafi and Maliki schools, the Mohrim should not cut the hair of another Mohrim intending to get to Tahallul state.
Allah knows best.