The Polyjuice Potion

Left alone to wait for Dumbledore, Harry looks around the office. He puts on the Sorting Hat, who again affirms his assertion that Harry could have done well in Slytherin, but Harry cuts him short before he can finish his thought. Harry then notices Fawkes, who unfortunately bursts into flames, thoroughly freaking Harry out just as Dumbledore enters. Dumbledore explains about phoenixes and informs Harry he doesn't believe Harry to be the culprit (because he already knows who it is, of course) and then asks Harry if there's anything he should know, to which Harry answers no.

The Christmas holidays arrive and the trio put their plan to trap Malfoy into action. After Christmas dinner, the boys trick Crabbe and Goyle into taking a sleeping draught and steal a bit of their hair. They then join Hermione in Moaning Myrtle's bathroom and they all take the potion. The boys transform to look just like Crabbe and Goyle, but Hermione refuses to come out of her stall, so the boys head out to find the Slytherin common room on their own. As luck would have it, Malfoy finds them and takes to the common room, where they discover, much to their chagrin, that Malfoy has no idea who's opening the Chamber of Secrets. At the end of the hour they return to the bathroom, disheartened at finding they're no closer to the culprit, though at least Malfoy let slip some information Ron will be able to pass on to his dad about Lucius. They're anxious to tell Hermione what they learned, but discover that Hermione has accidentally changed into a cat and they hurried her off to the hospital wing.

Here's what I don't get about the Polyjuice Plan, say Malfoy had confessed, what exactly were they going to do about it? Several times in this chapter it's implied that when Malfoy confesses, everything will be resolved and he'll be in trouble. So the plan is to get the confession, then go tell Dumbledore or McGonagall that they had fraudulently gotten a dangerous book out of the Restricted Section, stolen potion ingredients, rendered two boy unconscious, stole their hair and shoes and locked them in a closet, taken an illicit potion and then coerced a confession out of Malfoy? It would then, of course, turn into a case of he said, they said and let's face it, the rivalry between Harry and Malfoy has certainly not gone unnoticed by the teachers, so are they really going to take the trio's word for it? I suppose they could dose everyone with Veritaserum to ferret out the truth, but still I imagine the trio would have all gotten in quite a lot of trouble as well. I suppose one could make an argument that the punishment would be worth it if the attacks stopped, but I still question whether or not any of them had fully thought out the consequences of their plan (obviously not or Hermione wouldn't have turned into a cat).

As always, your comments are appreciated!