So the question is- if title's wrong, where can I go next to get the docs that prove the 3 beds are original?  

Removes the question of "where should be eat/go".   

Either a small single-family where you rent rooms to your friends or a multi where you do the same in one side and rent the other side as well.

Tax Benefits Once Built- Deduct depreciation and cost of maintaining the property - Deduct mortgage interest if a loan is taken outWhile I am not an accountant, I do not see where it would save you much, if any money at all.

Any thoughts on how you'd split profit in the case where the is land used as collateral without co-signing (if that's even possible with lenders)? 

And even in areas where the HOA allows it, the neighbors could rally against you and make it very hard in old school HOA areas.

Are there large trees between the house and where the sewer hits the street?

Properties that were converted a long time ago, or likely converted without permits, and not to today's building regulations.Not knowing how the property was separated by its units means that you don't know where the electrical, plumbing, or other mechanicals run.

There are other investor products available to where you do not need tax returns to qualify.  

I live in a county where there are quite a few decent looking abandoned homes and can never get far finding the owner and trying to find value on MLS is rough!