The context states that the legal entity is "não colegial" (non-collegiate), therefore "council", "committee" and the like would not be an appropriate translation.

"Fábrica da igreja" translates literally as "church's fabric" when referring to the Catholic Church's estate:

"The author has given a comprehensive description of the church's fabric, including the materials used in its construction, the layout of the building,..." https://www.amazon.com/Cathedral-Church-Bangor-Account-Histo...

"The vast majority of the church’s fabric belongs to the middle or third quarter of the 15th century and is built in a style called Perpendicular Gothic." https://www.mortarandco.com/post/ketterings-oldest-building

However, in this particular case, the term is related to the Church's legal structure. I suggest "ecclesiastical estate manager" since it involves a single individual, as explained in the context itself.

Example Sentence

Pope Gregory chided the ecclesiastical estate manager on Sicily: “You gave us one bad horse and five good donkeys: I cannot ride the horse because it is bad; I cannot ride those good donkeys, though, because they are donkeys!” https://ebin.pub/theoderic-the-great-king-of-goths-ruler-of-...