The assessed value is something that you try to keep down as an owner, and the market value is not really correlated strongly in a lot of cases with assessed value.

The OP is currently exploring conventional rehab loans (presumably 203k or similar) which would indicate that he is intending to owner occupy, and therefore hard money loans are likely off the table (as most HMLs are not NMLS licensed and don't make owner occupant loans).That said, to the OP, if you're looking at a conventional rehab loan you're just going to have to accept higher costs, less flexibility, and more red tape.

"Who needs the bank" by Bob Zachmeier is a great, fast read on the basics of owner financing. 

Hi Babu,A simple rental property balance sheet will have the following accounts:Assets: Cash, tax and insurance escrow, fixed assets and depreciationLiabilities: Credit cards, security deposits, and loansEquity: Opening balance equity, owner's contributions/distributions, retained earnings and net incomeThere could be a number of reasons that your balance sheet does not balance.

Should I be reaching out to current owners to find out if they are willing to sell their property and get more information about the property?

This could mean a vendor to owner relationship or a sub contractor to vendor  relationship. 

The property owner let the building decline for many years, but the location is prime.

. - If a pet is involved, there are third party pet verification services that you can contract with to help assess the risk of the breed.

I'm considering purchasing a condo that is non-warrantable (not eligible for conventional financing) because one owner owns too many units and there is a pending lawsuit against the HOA.

Typically the "owner" of the "firm," on paper, is simply a Loan Officer or Branch Manager, and all "his" employees are actually Loan Officer Assistants with pay-stubs that say "XYZ Lending" on them.