QIf 2 followers are put from my field into the cemetery at the same time, does this follower's automatic ability trigger 2 times?

AYes, it does. Note that this follower's automatic ability also triggers if it itself is put from the field into the cemetery.

QIf a Ghost I control is destroyed during combat, does this follower's automatic ability trigger?

AYes, it does. However, it would not trigger if a Ghost is banished due to its own "At the start of your end phase, banish this card" ability.

QIf I bury Hell's Unleasher to pay for its activated ability, does this follower's automatic ability trigger?

AYes, it does.

QIf a token follower on my field is put into the cemetery, does this follower's automatic ability trigger?

AYes, it does. The token is put into the cemetery, then it is immediately removed from the game.