I will start with what I found today. Having entered the same room where Akane also found Delta, I spent some time exploring while she questioned him. I was able to find this book of illustrations, apparently for a poem called Dante's Inferno. Inside that book I found an image of what is clearly Zack and his family if we need any more confirmation of him and Zagreus' connection. The woman in this image's portrait was also found on the bedside table- suggesting this is her and her spouse's room.

Also in the book one of the images was torn free, though there seems to still be some left behind that I have yet to examine in full. I can also confirm anything Akane found, as I was i the room with her.

As for contracts, there is something I feel comfortable finally confessing. Though I suspect it will not be a surprise to you all. Delta and I have been allies since the start of this loop, and not simply as Fabricator and employer. He is in fact the one that caused my SHIFT into this timeline, and gave me my mission.

...though do not think we are friends in any particular way. I DID try to stab him when I first woke up. Sadly I no longer had my weapons. Oh well.