Short answers, pulled from the story.
Ghibli Park officially opened its first three areas on the 1st of November 2022. The Grand Warehouse, Hill of Youth, and Dondoko Forest were the initial zones available to visitors at that time.
Hayao Miyazaki joined the planning process directly while his son Goro took on the role of director and lead designer. Toshio Suzuki announced the plan in 2017 and Studio Ghibli formed partnerships with the Aichi Prefecture and the Chunichi Shimbun newspaper by 2019.
The scope shifted from a small attraction to a massive five-area complex covering nearly 300 hectares. This entire project spanned four years from groundbreaking in 2020 to full completion in spring 2024.
The Valley of Witches district is located as one of the final zones alongside Mononoke Village in the spring of 2024. It officially opened on the 16th of March 2024 after being pushed back from its original schedule.
The heated swimming pool that once sat at Expo 2005 closed its doors in 2018 before becoming Ghibli's Grand Warehouse. Inside this converted space an Air Destroyer Goliath measuring six meters long floats above ruined gardens from Castle in the Sky without adding new rides or roller coasters.