Also, are any Greek or Roman mythological characters or creatures mentioned in the Bible?
Yes, several different Romans and Greek gods are mentioned. Artemis, Zeus, and Hermes are all Greek gods and Ashteroth was known as Astarte or Aphrodite to the Greeks.
Artemis was also known to the Romans as Diana and Ashteroth was known to them as Venus.
Thanatos, Hades, and Tartarus are mentioned too, though more in relation to the places (though they are anthropomorphized).
Thanatos (Death) is described as the last enemy that is destroyed.
The bible also says that all the "gods" of the Gentiles are in fact demons.