General synonyms:
* Loyalties
* Faithfulnesses
* Devotedness
* Allegiances
* Commitments
* Truths (referring to faithfulness to an original)
More specific synonyms:
* Accuracy (referring to faithfulness to an original, e.g., a reproduction)
* Integrity (referring to faithfulness to a principle or code)
* Reliability (referring to faithfulness to a promise or obligation)
* Constancy (referring to faithfulness over time)
To choose the best synonym, consider the specific meaning of "fidelities" in the context you're using it.