Hello! I'm Kevin and I work in the Departament of Translation of Pokémon Sun and Moon and today I'll explain some info about the game:
-Type: Null is a limited version of Marshadow.
-There is some areas where you can build your own Gyms.
-Jangmo-o is the Pseudo Legendary.
-Tapu types are: Electric (Tapu Koko)/Fire (Tapu Ikaika)/Water (Tapu Molukuu)/Ghost (Tapu Makau)
-New Alola Forms: Fearow, Weezing, Jynx, Parasect, Golem...
-Sinnoh legendary for moon: Cresselia. New Exclusive Z Move called "Moonlight Link".
-Sinnoh legendary for sun: Drakrai. New Exclusive Z Move called: "Deep Sleep".
-New UB 03, who's a squid.
-New Black Dolphin Pokémon.
-New Abyssal Ruins like in Unova but with a Legendary Pokémon.
Please stop saying Greninja Ash is in the game, it's an Exclusive Pokémon for the anime like Mismagius + Rayquaza.
-3 Prof. in Alola: Kukui, Lusamine (she studies the UB and the composition of their bodies) and the cousin of Oak who studies the Alola Forms.

;)