sadlessofabean

In Doppelganger the FL does exist twice at the same time, independent from one another, while in EotS she is reincarnated, keeping the same look.
There exists a friendly rivalry/hatred for one another/understanding.

Both female leads are seemingly replaced, but both coexist.
In Doppelganger it is an actual copy of the female lead while in TQoA it is a lookalike.