For a book the size of an greatly expanded 5e, which will be referenced as often as the core rules will be, I would consider a Smythe-sewn binding a must.
The current core rulebook includes basic material on the Order and Mythic Europe, so I'd expect it to be included. However, much of the material on the Order, the names of most of its key covenants and the foibles of each regional Tribunal, is in other books. Whether we can use that will depend on whether material is added to the core, or if those books are re-released under open licence.
We are still refining exact plans, but licensed matter will definitely include setting as well as rules. We want third parties to be able to make and sell adventures, sourcebooks, remixes, variant settings, variant rules, novels, comics,... without needing any individual negotiated license from us.
When we've talked (internally) about open licensing ArM, your novel proposal in fact is one of the examples I pull out as "we need to make it easy for this sort of thing to happen."
The system requires is to choose a date and time. I think a countdown is the only thing that is public-facing.
Actual launch date is subject to change, but within our master schedule of things for the year, including crowdfunding days, this is a likely target. If not Sept. 10th, I'm going to tell you on the sly that it is very probably going to be on a Tuesday at 10 AM central within the four weeks after that.
We would have preferred to say "this fall!" but the BackerKit Launch system requires specificity, even if subject to change.
I agree, Michael, that it will need Smythe-sewn binding. (Unless we wind up presenting it as a hand-carbed ebony box of embossed copper sheets or something, which is highly unlikely, but I don't want to preclude any possibilities.)
I'd like us to settle on production details that will be known (and budgeted and quoted from printers) from the start, not contingent on stretch goals.