You have a spot on description of Percy-
'Not so tall as Ron, nor so loud, but unmistakably from the same stock. Percy Weasley wore his red hair in a dignified style that set off his high forehead. His freckles seemed tamer than his brother’s but his eyes were just as blue behind the glasses that he wore. '

And he is kind and makes good suggestions-

‘Try talking to some of them about your work,’ he suggested. ‘See what suggestions they have. Get to know them a bit. And,’ he smiled engagingly, ‘when they give you a nickname, that’s when you’ll know you’ve really made it.’

His suggestion identifies the obvious problem-
'one of the witches in the room - whose name might have been Charlotte, or possibly Camilla or Claire'

I write Percy rather more Bureaucratic. When he writes, he always chooses the most obtuse explanation. Think the report on the thickness of cauldron bottoms. You could fiddle with some of his utterances to make him both caring and still a bit pompous.

But I enjoyed the story line. 'Christy-doll,' Indeed!