Mrs Gardiner's recollection is vague. I agree with your last point. She's just heard Wickham's sad tale, she's trying to remember Darcy's repute as a lad...then recollects a 'proud ill-natured boy'. Mrs Gardiner's memory is not clear after her long absence from Derbyshire. Perhaps the boy she heard of was not necessarily young F.Darcy. This had confused me as JA doesn't appear to put in even minutest detail without reason. :)