Misc: at what age does a filly become a mare and a colt become a horse?

Questions

A woman with a fine prospect of happiness behind her?

To perform successively and successfuly mastication,humectation & deglutition?

Kazantzakis novel which became an Oscar-winning film in 1964?

Of which country is Juan Carlos king??

What was the first name of tycoon Donald Trump's first wife??