Is divorce by the words, "You are divorced, divorced, divorced, by three" considered a single revocable divorce by a new contract, or is it an irrevocable triple divorce, especially since the Mufti ruled that the woman is a stranger to her husband?

The divorce certificate is not a condition for divorce to occur. The majority of scholars hold that a triple divorce pronounced in a single utterance counts as three, and that a menstruating woman is subject to divorce, and this is the strongest opinion. If the husband uttered what you mentioned, even if you were menstruating, then the major separation has occurred. The view of Sheikh Al-Islam Ibn Taymiyyah is that divorce during menstruation does not occur because it is an innovative (bid'i) and forbidden act. Since the matter is subject to disagreement, it is advisable for the couple to go to the Sharia court to resolve the dispute.