Descendants of Bharata? Bharata the king? the people would have been the same initially (I dont disagree), but the location of the Vahlikas exposed them to outside influence (Persians, Bactrians etc) due to which with the passage of time they would have induced variations in the things being practiced there with reference to other areas of the subcontinent.
As far as I see reading these texts, it seems as if by Mahabharat (Vedic) times, subcontinent was already divided into various kingdoms who lent support to Kauvaras or Pandavas.
Have you got any other reference to their culture, maybe something from another source?