This is plausible, but do you have any evidence? It's hard to know what the Meltrandi were after when they folded in before the last battle. Bodolza thought they wanted to steal the secrets of Protoculture and use it against him. Max may indeed have told them enough to whet their curiosity, since Hikaru and Misa probably told him what they knew before the fight with Millia. But were they there to help the humans, or simply to continue their existing feud with Bodolza?
I have 2 pieces of evidence:
1.)
When Minmay started singing the behavior of Max and Millia indicated their happieness with the situation as they were smiling at each other. After that they were seen flying allong side the Macross and tearing up the Bodolza sided forces.
2.)
DYRL is based on the TV show and Max, was never a traitor there. In the TV show Max won over Millia, in the Movie Max won over Millia.