No saint has really lost their saint title. Several saints have been removed from the official calendar of saints because we lack evidence that they really existed and may have been fictional characters rather than actual people. Some examples:
St. Christopher
St. Barbara of Nicomedia
St. Dorothy
St. Philomena
St. Olivia
Some people have been removed from the calendar and then placed back on it when additional information or evidence is found. An example would be St. Catherine of Alexandria.
St. Christopher is the most well-known Catholic saint whose title and feast day were removed from the liturgical calendar in 1969 by the Vatican due to historical uncertainties about his existence.
No, St. Dinah is not a recognized Catholic saint. The name "Dinah" is not listed in the official Catholic Saints Index.
Saint of the Sick and those who have lost parents.
There is no recognized saint named Tatum in the Catholic tradition. "Saint" is a title given to individuals who have been officially canonized by the Catholic Church after a thorough process of investigation.
Doctor of the Church
He was never sainted by the Roman Catholic church, his title "duc de saint simon" was a birth right title given to his father. Saint Simon was a place, thus the title of Duke of Saint Simon.
Rachel was an Old Testament Jewish Matriarch. While she is a saint, Old Testament personages are usually not accorded the title of saint.
Mary with baby Jesus
The Roman Catholic Churchconsiders him to be the first pope, ordained by Jesus in the "Rock of My Church" dialogue in Matthew 16:18
Yes, Saint Damian, the brother of Saint Cosmas, is a Catholic saint.
There is no official Catholic saint by the name of Saint Zoe. Saint Zoe is a common name for girls in Greek Orthodox tradition, but not in the Catholic tradition.
Not yet. She was "beatified" in 2003, which makes her a kind of vice-saint (the title used is Blessed), but has not yet been canonized.
Yes, Saint Augustine is a real saint. He was a Christian theologian and philosopher who lived in the 4th and 5th centuries and is recognized as a saint by the Catholic Church as well as other Christian denominations.