Light trails question(not using particles) and complex timeline

This is what I created:

1)How to make trails last longer ?
2)If I want to copy this part of a animation after another one, is there an easier way to animate ? Now, I have used timeline with every object. I tried with

parent to empty

but didn’t come out as it should.
3) Could the lighting be improved of overall scene and objects ?

To make them last longer change the values of the Bevel Factor’s end.
In the graph editor or the dope sheet change the values for the second keyframe of the end bevel factor and slide it to the right on the timeline.
That will give you longer streaks.
sample file here: