Have you considered this guide?
It's imo amazing and of very high quality. There are many, very detailed charts and maps of Lucis (and Altissa) in it. It feels like a real geographical atlas. There's also a big poster included of the complete world map.
Included are also 30+ pages of art work of the characters, creatures and the world. Especially the Altissia art is amazing. So much wasted potential...it almost physically hurts.
Regarding the festival:
I have the hope, that the weird, floating island that they showed us, is not how it will actually look like. Some of it is painted anyway. You will notice, if you look closely enough:
Instead of this floating thing, I hope they will add the pink outlined part of the city to the explorable area and there the festival takes place:
(The blue area is the area the player can now explore.)
We now know this area is almost finished (wasn't even
@DestructionBomb there?) and it really looks as if it should be part of the explorable area. It's weird that it is just walled off. There is a brige leading to it in the game and the bridge ends at a wall...
I also hope, that when the festival is over, they will add that city part permanently to the rest of Atlissia's explorable area.