Can you actually list each document, including dates?
From what you've posted above, I can't tell you whether each document meets the requirements or not.
For example, usually 7 months of payslips and bank statements are needed in order to cover every single day of the 6 months... but without knowing what dates your payslips and bank statements cover, I can't say whether they meet the requirement.
Similar with the correspondence - I can't tell you whether they are okay or not without knowing how many documents you have, the dates on the documents, the names on them (i.e. joint or individual), or the document source.
Are you both named on the lease?
- If so, you don't need a landlord letter
- If not, you do need a landlord letter.
You don't need any birth certificates.
You only need the sponsor's current passport, no previous ones.
You only need passports that you have held since moving to the UK (i.e. if you have renewed your passport since moving, you provide the old and new one. If you haven't renewed and still use the passport you arrived in the UK on, then you just provide that one passport).