The Grand Organ survives! In what condition it’s in is anyone’s guess.

https://www.kcrg.com/content/news/Notre-Dames-organ-survives-the-fire-508632421.html

Here’s an article on what else has been saved and what may be lost, though it was posted last night. You may be able to find more up-to-date information if you have the time to really look.

https://slate.com/news-and-politics/2019/04/notre-dame-cathedral-fire-art-saved-destroyed.html

The challenges and realities of rebuilding a Gothic cathedral:

https://arstechnica.com/science/2019/04/notre-dame-cathedral-will-never-be-the-same-but-it-can-be-rebuilt/