Yeah that makes sense to me, especially if the contact is broken because Shisui gets caught with correspondence and/or it gets too difficult to sneak letters out any more on her end. I'm still gonna keep trying to track down s2 so I can do better matching tone and so on... right now the best I've got is the Mononoke episodes set in a similar Imperial Concubine House scenario. XD

But yeah, Hiroe can produce illusions, among other things... although she needs to let her fox side show through to do it, so she's obviously cautious if it's a "suddenly, powers are unexpectedly needed" situation. If it's planned and/or she can disguise herself in advance, though (e.g. showing up masked as Zenko), she can be pretty flexible with it.