It wouldn't take long, so it would work; the other method from then was to make the leading probe a big mirror on one side -- it would turn and the big-assed laser in orbit around our Sun would shoot the beam, which would reflect against the trailing probe. But of course, none of this has been demostrated.
Again, that would constantly accelerate the front craft away from the following craft. It would require ever-increasing precision in aiming the front craft's beam or positioning the following craft, and would result in an ever-decreasing received beam strength.
It wouldn't take long.
I strongly doubt that. What is your source?
I suspect that when the numbers are all added up, this Rube Goldberg scheme will be shown not to work. But, I could be wrong. In any case, we're a long way from your "duh," which I hope was a joke.