What is the difference between a claim for breach of fiduciary duty and one for breach of a non-solicitation or non-compete agreement under New York law?

In truth, there is a lot of overlap between these kinds of claims, particularly because the facts that will underlie those claims are often one and the same. That said, the proof that will be required to establish these claims does differ. For more on this topic, please see "How Non-Solicitation & Breach of Fiduciary Duty Claims Overlap Under New York Law."