Short answers, pulled from the story.
Aristophanes presented The Birds at the City Dionysia festival in Athens during the year 414 BC. This performance secured second place among competing comedies and occurred during the height of the Sicilian Expedition.
The two middle-aged men who guide the plot are Pisthetaerus and Euelpides, while the Hoopoe serves as a transformed king named Tereus. Other key figures include the Nightingale wife of the Hoopoe and various gods like Zeus, Poseidon, Heracles, and Iris.
Pisthetaerus names the sky-city Nephelokokkygia which literally means cloud-cuckoo-land or sky-cuckoo-city. He orders his friend to oversee building walls for this new settlement where birds become the new gods.
Alcibiades appeared indirectly through mentions of the state ship Salaminia sent to Sicily to fetch him back for trial after he was suspected of involvement in anti-religious activities. He escaped custody before reaching Athens and authorities offered a reward of one talent of gold for his death.
A delegation from Zeus arrives consisting of brother Poseidon, oafish Heracles, and barbarian Triballus god. Pisthetaerus outwits Heracles who bullies the barbarian god into submission leaving Poseidon outvoted as the delegation accepts terms.