.- Also, you need a legal way to take back the deed if buyer defaults!

Interesting, since when did it become HRs problem (or legal right) to determine that "he is supposed to have found housing already".

For example, are there specific documents or information I should prepare, or would identifying a target property first be more beneficial?

Talk to the management company and if you're not feeling things are right or legal, then take legal action.

@Asher M.Possible, yes but like your lender pointed out it's going to be difficult to pass the self-sufficiency test (SST) for a legal 3-4 unit property.

Here's a good folder setup.Bank StatementsCredit Card StatementsProperty Management StatementsMortgage StatementsSTR Platform StatementsInvoicesReceiptsClosing Documents (Purchase/Refi/Sale)LeasesCheck & Deposit ImagesVendor ContractsW-9’s & 1099’s

This eviction altogether cost me $20,000 - legal fees, lost rent, and rehabbing.

HML is the same as getting a mortgage from a regular lender such as a bank or credit union, but the HML does not require as much documentation and they provide money really fast say, within a few days. 

They didn’t and according to him, that gives me the right to pursue the previous owner legally.

Some lenders specialize in this area.Legal and Tax Implications: Consult with a real estate attorney and tax professional to understand the legal and tax implications of owning an STR in a different state.I'm happy to answer any specific questions you have about my experience.