I have a question regarding required documents for tier 2 dependent visa. The rental agreement and council tax bills are mandatory? or people attach them just to be on safe side?

Proof of English proficiency is required for the main applicant, not for dependents.

Can anybody please respond to the question, whether rental agreement or council tax bills are mandatory, when applying for dependent visa. The guidance (see the links below) provided by the UKBA website does not mention anything about them. https://www.gov.uk/government/uploads/system/uploads/attach...