Short answers, pulled from the story.
George Lucas created the Ewoks for Return of the Jedi because he wanted a tribe of primitive creatures capable of defeating the technologically advanced Galactic Empire. He had originally intended the scenes to take place on the Wookiee home planet, but as the Wookiees became skilled with technology across the film series, Lucas designed a new, smaller species instead.
Ewokese is based on Kalmyk, a Mongolic language spoken by the Kalmyk people of Russia. Sound designer Ben Burtt recorded an 80-year-old Kalmyk refugee named Kosi Unkov telling folk stories, and those recordings formed the phonetic foundation for the language performed by voice actors in the film.
Warwick Davis played Wicket in Return of the Jedi, stepping into the role after Kenny Baker fell ill with food poisoning. Davis was eleven years old when he began work on the film in January 1982, and his grandmother had heard a radio ad calling for short actors.
Make-up artist Stuart Freeborn developed the Ewok design using the image of the Griffon Bruxellois, a dog breed owned by George Lucas. The result was a stocky, flat-faced biped standing about one metre tall, covered in fur with large jewel-like eyes.
Both Ewok television films won juried Emmy Awards for Outstanding Special Visual Effects. Caravan of Courage: An Ewok Adventure won at the 37th Primetime Emmy Awards, and Ewoks: The Battle for Endor won at the 38th Primetime Emmy Awards.
George Lucas based the Ewoks' defeat of the Galactic Empire on the actions of the Viet Cong guerrillas who fought against American soldiers during the Vietnam War. The parallel was intentional, framing a low-tech, determined force overcoming a militarily superior occupier.