Short answers, pulled from the story.
Leleākūhonua was first observed on the 13th of October 2015 by astronomers David Tholen, Chad Trujillo, and Scott Sheppard at the Mauna Kea Observatories in Hawaii. The discovery was formally announced to the public on the 1st of October 2018, following years of orbital confirmation.
Leleākūhonua means "it flies until land appears." The name is composed of four parts: lele ("to fly"), ā ("until"), kū ("to appear"), and honua ("land"). It was formally assigned on the 3rd of June 2020, proposed by students in the Hawaiian-language program A Hua He Inoa.
The informal nickname "The Goblin" was given by the discoverers because the object was found close to Halloween and because of the letters in its provisional designation. The nickname was used before the object received its formal Hawaiian name from the International Astronomical Union.
Leleākūhonua orbits the Sun at distances ranging from about 65 astronomical units at its closest to roughly 2,800 AU at its farthest. At the time its orbit was studied, it was approximately 78 AU from the Sun, about two and a half times farther than Pluto's current position.
Leleākūhonua's orbit, along with those of several other distant trans-Neptunian objects, is consistent with the gravitational influence of a large undiscovered planet called Planet Nine. Sheppard and colleagues concluded the orbital clustering suggests, but does not prove, the existence of such a body.
Leleākūhonua is estimated to be about 220 kilometers in diameter, based on a single-chord stellar occultation recorded at Penticton, Canada, on the 20th of October 2018. An earlier estimate of roughly 300 kilometers assumed an albedo of 0.15; the occultation data pointed to a higher albedo of 0.21 and a smaller body.