There isn't any particular terms for older Greek gods -- unless you mean the Titans, who weren't gods, but Chronos sired six of the original gods and goddesses.
Usually the Greek gods and goddesses were born of other, older deities.
They were born of older primeval gods and goddesses of creation.
Olympians.
No, they are myths. Hence the term Greek Mythology.
The Gemini are Pollux and Castor. They are the older twin brothers of Helen of Troy.
The term "food for the gods" originates from ancient Greek and Roman mythology, where it referred to special offerings or delicacies made as tribute to the gods. These offerings were believed to be of the highest quality and reserved for the deities.
In Celtic mythology they are sea giants. They are considered to be older than the gods, and were vanquished in the battle of Moitura. Their story is similar to Greek mythology's battle between the titans and the gods.
In greek mythology Zeus king of the gods and equal to Jupiter the Roman king of the gods wwas first , Hades god of the underworld came later.
Yes, the Greek civilisation preceded (is older than) the Roman civilisation. Many of the Roman gods are in fact the Greek gods that have been given Roman Names - eg the King of the Greek gods was called Zeus and this god became same as the Roman's king of the gods who was called Jupiter.
Yes, the Greek gods are immortal.
No, the Greek gods are myth.
Gods from Greek Mythology:AphroditeApolloArtemisAthenaDionysusHeraHermesPoseidonZeus