Yuu is initially going to be a Kyuudou pracitioner rather than a Kendo practitioner. This changed when Silver was Promoted to Playable in game and reveal that the canonical Prefect has a talent for the sword and changed it to give it a reference.
The original conception of Lyle Martin is that he was originally a Pomefiore student OC by the name Ives before the author realized that there are no known first year students from Octavinelle and changed the conception to create the current Lyle Martin.