“Sir, we’re detecting a massive object emerging from hyperspace.” *Death Star shown on Scarif horizon.
See 7:05
https://youtu.be/RIftKRavXCg
Yes, it has light speed. I’d think the fully operational part refers to the multi-reactor laser. They’ve only tested the single reactor.
I don’t see why the blue planet shouldn’t be or become Scarif in ANH:R. It would connect the films.