Ruin Explorer
Legend
It could very well be a coincidence... but I think the fact that there isn't an adventure within the Theros book will only help direct people to the Dragonlords campaign adventure path.
I think it's unfortunate that they're both called "Odyssey of" (albeit WotC's is "Mythic Odysseys"), but one can hope so.
And it could be WotC's way of throwing Ohlen and the others a bone for coming to work for them.
Sadly not possible. The pipeline between a book being written, having the art done, and so on, and released, is pretty long - and Ohlen etc. were only hired fairly recently.