Isobel was Bobby Gentry why wasn't she star of Movie?

Her cousin was Shirley, MacClaine and Jones. What about Moreno? MTM? Marlo Thomas?
How did a non relative get the lead?
What's also interesting: Katherine Hepburn was also Rita Hayworth whose daughter was in fact Isobel who died in 1969.
She was the real tall athletic swimmer Natalie Wood.

The fake Natalie was a horrible person and actress.
She possibly faked her own death to save her family embarrassment.

A tie for Oscar really? Interesting.
Her other daughter died in 1964. She disappeared. Never recovered her body. She was a child star who was the real Claudia Cardinale.

The fake Hayworth was a nut.