Ultra is never identified by name as a Catholic, but it is clear that she comes from a strong Catholic family. Ultra is a Mexican-American and a Hispanic (or "Latina"), although her ethnicity is not a major plot point or the dominant aspect of her identity. Ultra's mother frequently calls her, and uses Catholic-specific vocabulary and forms of cursing.
In most ways, Ultra exhibits very conservative ethics and personal morality. At one point in the limited series, she rails against her best friend, fellow super-heroine Aphrodite, for being sexually promiscuous and for trying to push her (Ultra) to follow suite. When Ultra dated Captain Steel (a popular superhero from Boise, Idaho who was apparently raised in a strict Mormon family), the media assumed that theirs was a chaste relationship and church groups even pointed to the couple as an example of a morally straight dating relationship. The media apparently made such assumptions about their relationship based on the "squeaky clean" images and the religious backgrounds of Ultra and Captain Steel. (Both were raised in churches with strong teachings against premarital sex.)
Despite Ultra's image, background, and her self-professed moral values, during the course of this limited series she goes to bed with a man on their first date. (This choice turns out disastrously for Ultra because while she was sleeping her date took photos of them in bed together, and he later sold the photos and his misleading account of their time together to a seedy tabloid newspaper.)
The most likely assessment of Ultra's religiosity is that she was raised in a staunch Catholic home and retains a considerable degree of Catholic consciousness, but she is not an active churchgoer nor does she consciously regard Catholicism as an important part of her identity. In the superhero business, Ultra was at one time something of a "poster child" or cherished role model for teens. Due largely to the media's creation of a public persona for Ultra, there was some entanglement between this role and her conservative religious background, even though she had no interest in actively practicing Catholicism or being a "Christian role model."
Ultra is cognizant of the significance of her public status as a leading superheroine, including the significance of her status as a woman and a Latina. But Ultra isn't even interested in representing women or Hispanics. First and foremost, Ultra strives to be a good professional super-heroine.