Short answers, pulled from the story.
Astronomers David Tholen, Chad Trujillo and Scott Sheppard spotted the object on the 13th of October 2015. They used the Subaru Telescope at Mauna Kea Observatories in Hawaii to find this faint point of light.
Leleākūhonua travels from 65 AU out to about 2800 AU over a period of roughly 55,000 years. Its orbit has an eccentricity of 0.955 and currently sits inbound at 78 AU from the Sun.
Students in the Hawaiian-language program A Hua He Inoa suggested the name on the 3rd of June 2020 because the object reminded them of the migrations of the kolea or Pacific golden plover. The phrase translates to it flies until land appears and compares the orbit to the flight of migratory birds seeking home.
Observations at Penticton Canada on the 20th of October 2018 showed a single-chord stellar occultation event suggesting a smaller diameter corresponding to a higher albedo of 0.21. Initial estimates placed it around 440 kilometers under an assumption of 0.15 albedo.