1) You can see a complete list of changes here https://github.com/reasonml/reason-react/blob/a70d9e6b51ed0a... . We consider it a huge release partly because it adds some long-awaited bindings, partly because of the documentation improvements, and partly because of how community-driven the release was.
2) BuckleScript's creator works for Facebook and has both a specific focus and a long-term vision for the project, more details here: https://www.youtube.com/watch?v=iWEQjvGGiTA . He also regularly blogs about ongoing improvements: https://reasonml.org/blog . Facebook Web Messenger and other products are heavily reliant on BuckleScript. I would consider that to be production-ready.
2) BuckleScript's creator works for Facebook and has both a specific focus and a long-term vision for the project, more details here: https://www.youtube.com/watch?v=iWEQjvGGiTA . He also regularly blogs about ongoing improvements: https://reasonml.org/blog . Facebook Web Messenger and other products are heavily reliant on BuckleScript. I would consider that to be production-ready.