The guard on Daniels room is named Oster after a Producer on the show Steve Oster.
Opens with the quote, "We don't believe, we only fear."
Within the Catholic Church, there are different types of exorcism. What is typically shown in tv and movies can not be performed by every priest, these are called solemn exorcisms. In the past, local priests could and did perform exorcisms but often with great abuses. To limit that, only those approved by their local Bishop can perform what are called solemn exorcisms. As is said, the Church takes great pains to prove demonic possession but as a rule, unlike other Christians, Catholics don't believe demonic possession is common. That said, medical and psychological examinations must rule out medical reasons for the behavior before a solemn exorcism can be performed.
Monsignor is an honorary title that is given to members of the Catholic curia, namely those in service of the Pope. Traditionally it was a title granted to priests by their local Bishop. Priests had to be a certain age and have a certain amount of time since ordination to be granted the title. However, since 2014 this practice has stopped and only those in Rome working for the Curia are granted the title. For practical purposes, the word simply means father and can and is used as such in countries that speak Latin languages.