I wonder if this is filler. We don't know the year here the clothing looks 90s or 00s and these guy were up for some rapin' and I believe it was stated that Kanejo was an Orphan, what if one of these guys was/is Kanejo's father? or perhaps becomes the guy that taught him kendo. I know she stated that forward in time means she keeps her clothes, but what if that's a bad assumption since she's still wearing clothes during her 'present'
Honestly I'm probably putting more thought into this than the author, but honestly that's kinda the fun of an Okamoto Lynn series.