On the one hand, 12 year old Jean and 17 year old Hijikata might get along piss-poorly and mess up the task (bad for them, but probably fun for us!), but on the other hand it might be interesting to have Archer/Shirou and Hijikata meet! Hijikata will only properly remember it later when he's an adult again, but he really appreciates Shirou for having been a good Master to Medusa in her timeline, so he may end up totally puzzled as to why Shirou was there when he isn't on Ellipsa... or is he?

Of course we could do something with both!!