Welcome back, Bob!
Happy to see the lessons learned from ReScript are heavily applied to MoonBit. I was a little sad to see that it requires parameter annotations but I guess you can move faster with tooling support that way.
But you are moving crazy fast. How many people are on your team (paid?).
Concerning the package manager I am not sure. It’s nice to have big JS libs available. Probably just a wrapper or yarn/bun plugin could be enough for that (and also for managing bindings). Being similar to TypeScript is mostly good for the positioning of the language.
For a new language that compiles to native code I agree, you cannot do without a package manager. Great to see the vertical integration philosophy got brought to the next level!