Tellus or terra
No, Gaea does not have a different name. In both Greek and Roman mythology, her name is Gaea.
Gaea, Terra, Tellus are all the Roman (Latin) names of Gaia, Gaiê, Gê- a Greek goddess.
The Greek goddess Gaea was identified with the Roman goddess Terra.
Terra
Jupiter was his Roman name. In Greece he was Zeus.
No Demeter was not a cereal she was a Greek goddess in Ancient Greece, She was the goddess of agriculture and harvest. Her Roman name was Ceres, from which 'cereal' is derived.
There is no roman god of ice because they did not know that ice existed.
Achaea. Actually the name of a Roman provence in Greece, but it was a blanket reference.
The Greek equivalent of Jupiter, King of the Gods, is Zeus.
the name of a short cape worn in ancient Greece is called a chlamys.
Hellas
Doubtful. There might have have been someone with that name in ancient Greece (where the film was set) or in the roman empire (hence the ending -us)