Harry was a little more relaxed, but that didn't mean that he believed everything the ghosts told him. Contrary to what Malfoy thought, he did pay attention, but he didn't let it interfere with what he had to do, at least until the information became relevant.
When Ron arrived, he shifted so that he was mostly in front of Malfoy. "What day is it for me? Did they change the days of the week for me," he said with a grin. And sure, this might be Ron, but he might not be, considering that they had no idea what was happening. "Remember that first case, with Neville, we got stuck in a parade, couldn't use magic because of all the TV cameras. Do you remember the town?" No one but the three of them would know that."