Amulet coin does not affect shiny rate at all here. It's a consumable item which increases pokeyen drop from NPCs for an hour when used.
Not applicable here.
Not applicable here.
Not applicable here. Also 'Unknown OT' is not a specific player.
When a player breeds 2 non OT Shiny pokemons (or when atleast the species deciding pokemon is not OT), the game assigns 'Unknown OT' in the OT slot.
Counting the number of your encounters do not change anything. High encounters do not necessarily guarantee a shiny pokemon.
This is not applicable here either.
All you need to know about shiny hunting in this game
Here Shiny rate is 1/30,000 per encounter (PER ENCOUNTER, therefore you may have 100,000 encounters but may still not find a shiny)
Donator status increases chances of finding Shiny pokemon by 10% (making it 1/27,000 per encounter)
Shiny Charm (which lasts for an hour), the person who uses it has shiny chance increased by 10% for the hour it is active. Any other players in link with the Shiny Charm user have their Shiny finding chance increased by 5% for the duration.
tl;dr SRIF