The very last document we found was the biggest clue to your first question. We got there by (rot13) frnepuvat sbe plab-yrv. It's not signed but it's pretty clear who it's referring to if you understand the relevant words.
To your second question: that was something I only realised once we'd placed 29 out of 30 titles! But there are hints in documents such as (rot13) "Genafvg Fbyhgvba Ercbeg". We'd already been suspecting something like that given (rot13) gur inevbhf pbashfvat guvatf jr'er gbyq nobhg fbynnz: jr'er nqerffrq nf fbynnz, ohg gurl'er uhtr naq pna fgrc ba gerrirv, naq qvfnccrne ng avtug...