Agatha didn't eat Billy and Tommy. The comics don't have this storyline. Usually, characters' fates are determined by the overall narrative and character development, not by such extreme events.
Sure. Marvel has released comics related to the concepts and characters seen in WandaVision. They often expand on the backstories and offer additional adventures.
Tommy in the 'tommy good story' could be anyone. He might be a child with a vivid imagination and a heart full of goodness. Or he could be an adult who has had some remarkable experiences. Maybe he's a local hero in the context of the story, someone who is known for his positive actions.
Sure is! WandaVision takes elements and characters from the comics and builds a unique story around them. It weaves in familiar comic concepts while adding its own twists and turns.
Sure, there's a selection of Wandavision comic books available. They can give you a different take on the events and characters, and might even explore what could have happened next or in alternate timelines.