Which Pokémon can't be shiny in Sun/Moon?

According to Serebii this is the list of shiny-locked Pokemon in Sun/Moon:

• Tapu Koko (With the exception of the event Tapu)
• Tapu Lele
• Tapu Bulu
• Tapu Fini
• Cosmog
• Solgaleo
• Lunala
• Nihilego
• Buzzwole
• Pheromosa
• Xurkitree
• Celesteela
• Kartana
• Guzzlord
• Necrozma
• Zygarde

Probably also Magearna and Marshadow are shiny-locked like other Event-only Legendaries, they are listed in a different table.

It would appear that Solgaleo, Lunala, and the Ultrabeasts are shiny locked

Secondary sources here and here

Evidence that Type: Null is not shiny locked