They all have the same glow, I literally just changed the hue on the red when I was doing the other colours. All done the exact same way.
This won't be added because some players have bought more than one. Had whoever originally released sabers thought about this then a system like skins could have been added. If nobody had bought more than 1 then maybe it could have happened, but they have, and they can't be refunded for it.
And the onetime change thing also won't be added because we don't have any scripts allowing that, and as snk is busy with countryside he has no time to make a script just to allow a handful of people to change the colour of their saber once