Unfortunately, that's not possible at the moment.
You can rename the star through the Editor but this will not rename the system when zoomed out.

Once zoomed out the system cannot be selected when the Editor is turned on.
Probably an oversight as it was possible to do this in DW1.

What is the benefit of "Scientist Location"?

According to the Galactopedia:
"Scientists apply research benefits when they are onboard a research station [...]"

In my early game, the automation moved my first scientist (+7% hi-tech research) to my research station (+16% reactor research). Looking ...

That's a good question, I haven't found any options in the settings yet..
Even though I selected "1440p@144hz" in the "Display Mode" settings it's still capped at 60fps.

Congrats on the release btw