DALPA and NWALPA are already talking.
As to the other unions, I believe the combined merged company workgroups may have to take a representation or certification vote. In this case, the Delta people could have some influence because of their larger numbers.
As I was told by an NW FA, there would first need to be a representational election. There needs to be 50% + 1 support from the combined DL/NW FA workforce to even have ANY union.
Looking back, when NW was voting in the AFA, they had around a 70% or so voter turnout. When AFA tried to organize at DL a few years ago, the turnout was less than 30%. If those numbers still stood, the FA group at a combined DL/NW could very well be de-unionized.
Therefore, to get AFA representation at DL/NW, there needs to be a dramatic increase in DL FA turnout as well as an increase in NW participation to at least 90-100%.