Are there mods already for the others?

Are there plans to reborn the others?

Does it need to be a new save?

I don't have any current plans to make similar mods for the other planets.
You can use an existing save, turning on Recipe Compatibility Mode in Main Menu > Settings > Mod Settings will keep the vanilla recipes enabled so your existing setup doesn't break.

Alrighty thanks for the reply Zirdchona! Mod looks great so far :^)

Would be cool if you thought about making reborn projects for the other planets!