You always have control and nobody else, not even your attorney, can manage or sell your property except for you.If you need to prove ownership for financing or any other reason, you simply produce your company documents as well as your banking and accounting records.

Can we get copies of the last 3-5 years of Schedule E tax documents, or tax returns, showing profits & expenses?

Depreciation is calculated with this formula below:Cost of the Building- Value of the Land = Building ValueBuilding Value / 27.5 = Yearly allowable depreciation deductionMy questions are:What or which documents will provide me the 1. cost of the building 2. the value of the land so I can calculate the formula?

Sellers were highly motivated and had frequent and long time delays in providing documents. 

They might see only 5 square inches of termite damage...needs to be documented. 

If I wanted to update the principal balance and terms of the note, is that something I could just add to the existing documents as an amendment?

., you can use a self-drafted document as a contract.

Also, review the closing documents to ensure that the tenants' security deposit is credited to you and that it matches what is in the lease agreement. 

Both properties were rentals before and had great rental history.

@Ryan ThomasDocumentation, documentation, documentation!