Original Catwoman was created in the 40s, had no costume except a cat's head helmet once or twice, then stopped showing up.
In the Batman 1966 tv show brought her back as a parody of the then-new-and-popular James Bond movies. She's a Bond femme fatale in a *cat*suit. Get it? Selina was reincorporated into the comics, but as a costumes weird cat supervillainess.
Felicia is the fusion of the already rampant Bond influence at Marvel, the repeatedly failing "The Cat" brand, and 60s TV Catwoman.
Modern Selina is a combination of Felicia, Bronze Age Catwoman, and Frank Miller's Selina from Year One.
So Selina is a ripoff of Felicia, who is a ripoff of Selina, who both was and wasn't Selina.