What advantages did Catholic missionaries to the Indians have over Protestant missionaries in old Oregon Country?

There is a fairly long account of Catholic and Protestant missionary activity to the Indians of Maine in Lord, R. H., Sexton, J. E., & Harrington, E. T. (1944). History of the Archdiocese of Boston In the Various Stages of Its Development 1604 to 1943, New York: Sheed & Ward. This history is in three volumes; as I recall, all accounts of missionary activity are in Volume I.

By the Catholic account, the Catholics were far more successful than the Protestants. The causes of this were at least three:

1. The Catholic (there was only one missionary) ate Indian food with the Indians; the Protestants brought their own food and ate it with their families.

2. The Catholic missionary attended to the Indians' needs by, for example, showing them how to, and helping them, build small houses or cabins and a church, while the Protestants literally tore down whatever the Catholic missionary built and were apparently more interested in their souls.

3. The Catholic missionary came alone and devoted all his time to his job, while the Protestants brought their families with them and devoted a part of their time to them.

   From the answers I read above, I am assuming that the situations in Maine and Oregon were similar.

George A. Strieby gives an excellent answer of which I would like to expand on it a little.

Most Jesuits missionaries shared in the daily life of the Indians, travelling with them as they moved from one encampment to the next.

The two religious traditions took different approaches to evangelism. Catholics, such as the tireless Father Pierre-Jean De Smet SJ (missionary in the old Oregon Country), sought simple expressions of faith from Indians. Protestant missionaries, on the other hand, sought not only to convert Indians to Christianity but also to convert them to a new lifestyle centered on individual labor and community-building. - Missions and missionaries

The Jesuits tried their best to understand the Native languages that they were dealing with.

St John de Brebeuf noted that in order to be effective as a missionary, one had to master the Native language at hand.

To explain the low number of converts, Brébeuf noted that missionaries first had to master the Huron language. His commitment to this work demonstrates he understood that mutual intelligibility was vital for communicating complex and abstract religious ideas. He believed learning native languages was imperative for the Jesuit missions but noted that it was so difficult a task, that it consumed most of the priest’s time. Brébeuf felt his primary goal in his early years in New France was to learn the language.

He translated Ledesma's catechism from French into Huron, and arranged to have it printed. It was the first printed text in that language (with French orthography). He also compiled a dictionary of Huron words, emphasizing translation of religious phrases, such as from prayers and the Bible.

Brébeuf is credited with composing the "Huron Carol", Canada's oldest Christmas song, written around 1642. Brébeuf wrote the lyrics in the native language of the Huron/Wendat people. The song's melody is based on a traditional French folk song, "Une Jeune Pucelle" (A Young Maid). - Jean de Brébeuf (Wikipedia)

One last little note, I would like to add here is that the Jesuits incorporated to some degree native languages into their liturgies:

Algonquian and Iroquoian Uses

Also called "Indian Masses", a number of variations on the Roman Rite developed in the Indian missions of Canada and the United States. These originated in the 17th century, and some remained in use until the Second Vatican Council. The priest's parts remained in Latin, while the ordinaries sung by the schola were translated into the vernacular (e.g., Mohawk, Algonquin, Micmac, and Huron). They also generally featured a reduced cycle of native-language propers and hymns. At present they are rarely used. Latin liturgical rites (Wikipedia)

Catholic missionaries possessed a number of distinct advantages over the Protestants. First, they were well-trained, ordained priests, not merely well-meaning laymen, as many Protestants were. Unlike family men, they were free to travel about, to live among Indians, then among white settlers, then to move on again. They posed no threat of permanent settlements and growing families. Lacking personal ambition to farm or build upon the land, the priests could devote most of their time to religious obligations.

The Catholics seemed to be more forgiving toward the Indians, to be less demanding than Protestants. They were less shocked by Indian attitudes and by actions that people like the Whitmans viewed as horrid vices. Priests also accepted conversions more freely, too freely the Whitmans thought, without requiring continued instruction. They did not deliver moralistic sermons.

Catholics used objects that could be touched and seen: shrines, cups, and beads. Such symbols easily lent themselves to the Indian culture because symbolic objects were already familiar.