Probably because Hermes is in a lot of the myths. He is a greek god, so there were myths written about him.
the was the messenger god
Hermes helped many people in the Greek myths including Perseus and Odysseus.
Hermes (Mercury) was the main messenger depicted, but Iris is also a messenger in some myths
Not in the Greek myths.
I do not know of a Miaia related to Hermes. However, the mother of Hermes was called Maia.
I do not know where you have read about Hermes' murder trial. It does not belong to the actual Greek myths.
There are many myths centering on him.
Zeus is Hermes father.
Yes.Rhea was Hermes's grandmother.
Hermes is the son of Zeus.
It's a bit unclear. In some myths his father is Zeus, but more frequently it's Hermes or Dionysos.
It depends on what myths you listen to. In some he is a tricky self serving god of theives. In others he is kind and helps travlers and elderly folk