Disclaimer: I have not studied the current Atlantic conditions in detail, but a lot of the ideas seem reasonable.  I am not aware of widely used, real-time monitoring of the AMOC strength, but the AMO index has been slightly positive (i.e., warm) over the past few months.  The NAO has been predominantly positive this winter, which would tend to be associated with trade wind strengthening and MDR cooling, but the forecast is for a negative NAO tendency over the next week or so.  However, I am not confident in the persistence of this NAO pattern, and so I do not know if it will have major impacts on MDR SSTs.  You are right that the Gulf of Mexico and much of the North Atlantic has been warmer than normal.  The NMME forecasts (http://www.cpc.ncep.noaa.gov/products/NMME/seasanom.shtml) indicate a fairly high probability that SSTs in a broad region of the North Atlantic will remain above normal through the summer.