In my previous post I mentioned about Yadava-Ideya connection based on Ravi Mundkur's post on their etymology. I think that is a mistake.
I was reading "Caste, Society And Politics In India From The Eighteenth
Century To The Modern Age" by Susan Bayly. According to her, Yadava identity of cowherds in north/east India is a recent phenomenon. During 19th century many castes tried to have a dignified identity for themselves in colonial India. Before nineteenth century cowherds were called Goala(Govala...literally cowherd) in those areas. In caste India, the name of the occupation also carries shame and can be used as an abusive word. Whatever the reasons the name Yadava is a new identity and can't be equated with Ideyar of South India.
However, this will change nothing in my arguments on the formation of Dravidian society. South Indian herders were also known as Golla traditionally (now many of them are taking up Yadava caste name). So that still shows continuity of Golla identity from north to south just like their R1a1.