Given Reformation controversies, it is easy for Catholics to see “sainthood” as an epistemological category: saints are those we are sure are in heaven. This is true, but it sounds like Catholicism played in the key of Calvin. Catholicism as such sees saints as a liturgical category: saints are those now made an explicit part of the liturgy. The certitude we have of the blessedness of the saints is not to provide us with some super-certitude about the possibility of salvation but because, for Catholics, revelation is liturgy, and so if the saint were not in heaven he could not be part of what God revealed to the world about himself.
Similar things can be said about the inerrancy of Scripture, although its de-contextualization from liturgy leads to far greater confusions. A reading from Genesis about the creation of the world means something far different in a liturgical environment than in the private study of a skeptical biologist.