Is Yae the True Electro Archon?

Yae is not the previous Electro Archon.

Who is the actual Electro Archon?

Ei is the name of the current Electro Archon and Makoto's sister. She's erroneously referred to as Baal — that's because the public is ignorant that the previous Electro Archon actually perished centuries ago.

Is Baal or Yae the Archon?

Baal was the original Electro Archon and Raiden Shogun of Inazuma, also known as Raiden Makoto. Yae Miko reveals to the Traveler that Baal and Beelzebul were twin gods. Five hundred years ago, the Calamity at Khaen'ria led to the death of Baal. Beelzebul takes over the role of Electro Archon and Raiden Shogun.