Harry is endearing at the times when he's most clueless, I sometimes think. In this case, he really should have realized the lie would have been useless even if Draco had believed it, thanks to the fact that the Ministry wouldn't. But he's like that.

Shacklebolt is playing a cautious game. If he reacts too strongly to Diggory, he'll seem frightened; if he remains passive too long, he'll seem weak.

There will probably be two trials simultaneously, Narcissa's and Harry's.

And thanks!