I think definitely getting in to the third part of the Epitaph where I do suggest Kinzo’s motive for writing is weak. My thoughts have changed on it a bit since I wrote it up, largely because I’m beginning to question how much of Kinzo we see is real and not just unreliable narration (and at this point I’m fairly certain he’s just dead when the gameboard starts). I don’t know what I have left to go off, and this narration problem certainly doesn’t help.
My main thinking behind it is a parallel I theorised between Battler not accepting witches, whilst Kinzo cannot accept Beatrice’s death. To further reflect this, I think it would make sense that if Battler cannot accept one of the people he cares for is the culprit, (despite all evidence to suggest it must be the case), then it would make sense that Kinzo also reflect this in that he could not accept his family as his own, despite a natural familial bond; so maybe the epitaph does reflect what care he has left for his family.
Of course, if the epitaph is addressed to Beatrice, it seems, by the closing line, so my immediate thought to your suggestion about resurrection is this; perhaps Kinzo has projected the image of Beatrice on to another person who the epitaph is actually addressed to. This may explain the idea of homunculi and human cages, by reflecting that Kinzo has forced this personality on someone else. If I bundle this in with the idea of a multiple personality culprit, as I suggested here, it would also make sense that Beatrice is one of the personalities.
This actually gets me thinking, if Kinzo did know about this other personality of the culprit, perhaps he also knew what they intended to do? Maybe then the Epitaph was trying to show them how they could get what they wanted without killing everyone. I recall that there was a suggestion that the epitaph was intended to let an illegitimate heir claim the Ushiromiya headship. I’m currently looking through our footage to see where that was.