Has Mrs. Freeze ever been resurrected in DC Comics, and if so, under what circumstances?

Yes, Nora Fries has been resurrected multiple times across different DC continuities. Often, these resurrections are temporary or come with complications. For example, she was briefly revived as a zombie-like being by Poison Ivy, and other storylines have involved attempts to transfer her consciousness or rebuild her body using advanced technology. These resurrections rarely provide a lasting happy ending.