I finally got Lonnie on the phone and he concurred that the XPA2 and M80s appear to be a mismatch. He states that with the original M80s the crossover did appear to drop below 1.5 ohm at certain frequencies (he didn't specify what testing was done). Lonnie also stated that the the XPA2 does not have a current limiting circuit as does the Rotel, this is an intentional design to allow the xpa2 to express the full dynamic range in an unfettered manner.
The only emotiva amp(s) he would suggest as a consideration to run the M80s would be two XPA1 monoblocks, which are able to go down to a 1.5 ohm load. These will be $999 apiece so the cost would go up quite a bit with that solution.
The sound of the XPA2 with the M80s at high volumes was quite good, however perhaps this is the definitive word regarding their incompatibility at just such high volumes.
"If you try to turn toward it, you go against it."