Brygians, Paionians and Makedonians as part of the same language group?
My basis for this idea is the fact that the Matt-painted culture, the culture from which Phrygians sprang, also occupies the entire Paionian and Makedonian areas. This culture lasted from roughly 1600bc to the early iron age (the period just before 700bc), with some of the Iron Age sites still being attested in Makedonia and Paionia.
There is no evidence to suggest that the Makedonians moved in from the south sometime in the LBA collapse or the Iron Age, or that they were not native to the region.

The Phrygian language, if Anatolian and other Substrate influence is deducted, would not be radically different from the Mycenaean Language. Makedonian likely represented a dialect continuum inbetween "Pure Phrygian" and Greek.

The Pella Curse tablet from 400~ years later bears resemblance to the Doric dialects, which tracks with the fact that the Argead dynasty were originally Dorians and the court language of the kingdom of Makedonia was likely represented a dialect continuum inbetween "Pure Phrygian" and Greek.