"B: La Nina's are statistically correlated to warmer Februaries. This is "field-presumptive," admittedly. If anyone has qualitative information I will not take it as refutation - be my guest. And obviously, like all inference techniques ... the interpretation should be used in the spirit of "tendency"
Caveat with this being your point about ENSO being less coupled with the atmosphere....we have certainly seen it this year with the WWB erupting in late Novie to kick off the extended PNA regime that we have been in. Not to mention this La Niña is very meager to begin with....weak ENSO are more prone to other influences, anyway, aside from any CC inference RE difficulty coupling.