1. None of them is correct. Please provide your translation.
2. The sentences cannot be in accusative, dative or any other case. It's nouns (or pronouns) which decline by cases, not sentences.
Consider: Сестра пишет пишет письмо другу брата карандашом на бумаге. = The sister is writing a letter to the brother's friend with a pencil on the paper.
сестра - nominative, письмо - accusative, другу - dative, брата - genitive, карандашом - instrumental, (на) бумаге - prepositional.