Good point about spin resonance, something I believe is common but rarely gets mentioned. If the M star system has other 'giant' planets 'nearby' within a couple std AU, the probability of resonance daily rotations increases dramaticly, given that the HZ planet's orbit was stable and didn't get perturbed and ejected eons ago.

The habitable ring tidal lock paradigm is for planets whose atmosphere does NOT freeze out. Current thinking based on models is that reasonably dense atmospheres will conduct enough heat efficiently to prevent this. I'm sure the winds would be something though. Worse than the stuff the damn Canadians inflict on us down here in NE. Were one side's air to freeze out the air from the warm side would drift over, freeze out and soon NO atmosphere.

Sure M stars need a billion +/- years to calm down from their frat party days of mega UV eruptions but even our solar system had to wait 800 million years for the surface sterilizing Late Heavy Bombardment to finish before life could stabalize on Earth.

By 19 June, Kepler is scheduled for its 1st download of occultation data. Lots of dips should be detected. Just several months will be needed to repeatedly detect all the fast orbiting HZ planets of early M stars; 3 times is needed for a ~3 sigma confidence of reality. The scientists will have their M star data in the bank before Thanksgiving. By then, the 1st hits on over half the G and K stars 'Earths' will be in the record along with beaucoup big fat inner planets.