I must have missed that discussion, so for the sake of keeping it as simple as possible, lets say that B fair caught the second kick.
If we're only concerned about whether they CAN kick it a second time, then how the ball ends up at the end of the play is moot. They CAN kick it as long as they recover it behind the LOS.
The discussion AB was referencing concentrated on who had the ball at the end of the play, not whether the second kick could be made. (Look out, AB, going there again!
) In a nutshell: K kicks over LOS but short; R muffs ball back over LOS; K picks up ball and kicks again; K downs the untouched kick downfield; did the touching by R during the first kick still count after the second kick and it's now K's ball where it was downed?; we pretty much came to the conclusion the second kick wiped away the touch by R during the first kick. It's R's ball where it was downed.