In terms of first songs, it varies on the teacher.
My tsugaru teacher started me on Rokudan Jongara - but only because I had a background in regular min’yo. Bachido’s initial song is Kuroishi Yosare Bushi, which is much more digestible than the denser Jongara arrangements.
A friend of mine usually teaches his students Ecchuu Owara Bushi or Kokiriko first. My regular min’yo group begins with Kokiriko (for dudes) and Ringo Bushi (for ladies).