Short answers, pulled from the story.
The Shakyas lived in the Terai, an area south of the Himalayan foothills and north of the Indo-Gangetic Plain. Their territory stretched from the forested regions of the mountains to the Rohni River.
The Shakya Republic functioned as an aristocratic oligarchic republic similar to the Licchavikas. Heads of Sakya clans formed an Assembly known as the Sabhā where leaders held the title of Rājā.
Suddhodana was a member of the ruling aristocracy during the fifth century BCE who married Princess Māyā. Their son Siddhartha Gautama became the historical Buddha and founder of Buddhism.
Kauśalya king Viñūda bha invaded Shakya and Koliya republics shortly after the Buddha's death. A long war resulted in massive loss of lives on both sides before annexation into his kingdom.
The Shakyas worshipped the Sun-god whom they considered their ancestor. They claimed descent from Sūryavaśa or Solar dynasty through descendant Ikshvaku.