Evidence Of Finances (Bank Statements, Payslips)

Hi,

Applying for ILR soon just wondering if these documents are for both couples last 3 months or 6 months and is this in addition to the 6 letters from 3 different sources?

Thanks.

Last 3 months pay slips, preferably last 6 months bank statements for both, in addition to the 6 proofs of joint address.
The proofs of joint address must come from at least 3 different categories and be spread over the full 2 years as evenly as possible.

is a letter a requirement if you cannot get joint names in 3 different categories?