Nobody bought
The plan was a gated estate of luxury houses with views of the sea. It was far from the city and buyers never came: only two houses were built, and Gaudí himself lived in one of them.
Eusebi Güell asked Gaudí for an exclusive garden suburb on a hill above Barcelona. Only two houses were ever built, and in 1926 the city opened it as a public park.

The plan was a gated estate of luxury houses with views of the sea. It was far from the city and buyers never came: only two houses were built, and Gaudí himself lived in one of them.
The mosaic salamander on the entrance stairs, known as el drac, is the park's mascot. Behind it, the Hypostyle Room's columns were meant to hold up a market for the residents.
The wavy bench around the main terrace is covered in broken tiles, a technique called trencadís, made largely by Gaudí's collaborator Josep Maria Jujol.
As a luxury housing estate. Eusebi Güell commissioned Gaudí in 1900, but only two houses were built and the city turned it into a public park in 1926.
Yes, in one of the two houses, from 1906. It's now the Gaudí House Museum.
For the Monumental Zone (the dragon, the bench and the Hypostyle Room), yes, with timed entry. Check the official site.