Who can assign tasks?
Any member of a board can assign tasks.
Who can tasks be assigned to?
Tasks may only be assigned to members of the board. Not members outside the board (other members of that project).
Can multiple tasks be assigned on a single piece of content? Can they be assigned to multiple people?
Who can Edit tasks? Delete tasks?
Any member of the board the task resides on may edit/delete a task.
Who can mark tasks complete?
Any member of the board the task resides on can mark a task complete.