It's always been easiest for me to convert any age-related things in Yamatai using the
calendar page's table. Maybe the least obtrusive solution for each article would be to footnote the first mention of student age on each wiki page to say something like ((Age information on this page is listed in standard years, see: [[faction:yamatai:calendar#irlearth_years]] for information on conversion to Yamataian years)).
I'm suggesting this method because it keeps a relatable basis for readers, who can then do their conversion themselves. And doubly because Nashoba isn't around to give his input on DoE, while
@Toshiro also seems MIA right now for Tsubomi. I think those pages that are updated to use Yamataian years in default still parenthetically mention Yamataian years are different so that, at the end of the day, people know their characters are still ultimately the same temporal age as they would be without the conversion.