The RLA restricts the ability to seek Self Help, but even without that the strikes have been deemed illegal during this process. So even in the unlikely scenario the unions receive a life line from the NMB, the precendent of a past strike indicates that is not an option.
Strikes are legal, just not for Airline workers, unless they get released by the NMB. That wasnt the case in 1983 when Continentals pilots went on strike in response to abrogation but thats what an appellate court decided a couple of years ago at NWA. They call that "Judicial Activism", Judges decide to rewrite laws according to their personal feelings instead of exploring the intent of the elected officials who wrote the laws in threory in response to the will of the people. Clearly the precent had been set that once a contract has been unilaterally abrogated that workers under the RLA could resort to self help just like all other workers who may find themselves in the middle of a C-11 reorganization, but the court decided otherwise, profitable airlines are better for Judges portfolios than fairly paid workers. Under the RLA changes in compensation are a major dispute and unilateral changes permit workers to strike. The law does not explicitely describe how a company could legally unilaterally change such terms, but it does say what our response can be, apparently C-11 is a means, but the Judges ignored it anyway and in effect rewrote the law to their liking.
BTW, the article you cited mentions that AMFA was on strike both before and during the BK.