pre-ordered my Vol 3 Dora yonks ago too, its marked "dispatched" but no sign of it yet...to be honest a little bit apprehensive re the contents given that Crandall Japo must have covered just about everything there is to know about the Dora, hopefully though Mr Creek will have much more on the operational history of the type compared to the other publishers..
I think it's fair to say that both assumptions are correct. I haven't had time yet to give it a thorough going over but initially it does cover much of the Crandall/JaPo material, it couldn't really not do that. The latter two thirds of the book does spend more time on operational use of the later versions, as well as a bit of "what iffery".
Cheers
Steve