There are ways to appeal if they don't count a unit, like referencing mid-1950 water records, but I wouldn't bank on that as a buyer. 

Your backup financing plan when the bank gets a note from LA saying their borrower has died?

My background into RE started when I began working as a commercial credit underwriter for a bank.

My thought is if I buy it outright and I get a renter, wouldn't I just refi. from a bank  and get all my money back for my HELOC.  

From an accounting perspective it seems to be working ok, but is there any reason to have one bank account per property?

How many times people say they don't trust bank accounts.

But you sign an Assignment of Agreement contract with the assignee (tenant/buyer) and the landlord/seller which states that the assignee assumes all rights, privileges and obligations under the lease and option contracts which are attached for reference, and that the landlord/seller accepts the assignee in place of assignor (you) and releases the assignor from all obligations under the attached agreements.It's very important to include that line and have the seller sign the Assignment, otherwise you are still liable to the obligations even though you've assigned the privileges away.You can't have your name removed from the contracts.

Never get attached to any investment property.

Specifically hows the financing, how do they appraise after the '"rehab," and do banks lend about 70% of the ARV as they do on residential properties?

It can be as simple as a form letter in the mail or attached to the door.