Why pay when majority of the info is going to be retrieved from multiple resources that you can exhaust for free.I just used a random home I knew the value on and went thru the above methodically.

This topic has been debated exhaustively on BP and in my estimation nobody has done a good job of explaining how it is NOT unethical to tie property up with zero intention of performing if you can't sell the contract.

According to HAMP guidelines the lender most exhaust all possibilities and take care of any outstanding issues (ie: hoa dues), usually the lender would of paid those, unless they were planning on just foreclosing anyway.

I personally would take a shot but I have a strong risk appetite (probably should remedy that at some point) but I know that is not the case for everyone and being highly levered can be stressful and exhausting sometimes.

Building had 1 Sewer/Water all other are 2 whole units but because of the water/sewer the mortgage/deed were under both of our names. 2010 This "Friend" stopped payment - I exhausted all avenues on trying to get them out and allow me to take over with no luck.  

I would also suggest an exhaust fan that would turn on when you turn on the lights or put a separate switch for it possibly time delay switch that way the fan would run for 30 minutes or longer.

The above is not an exhaustive list of why Corps make senses - do your research to discover more about their advantages.

The other contractor suggested we only need one 5" liner.Is there a ratio of exhaust to diameter that anyone can help me out with?

No, that's not the way to do it...unless you want to die from exhaustion before you turn 40 (or earlier).  

Most use the MLS, wholesalers, realtors, other investors, networking, telemarketing to owners, mailing to owners, door knocking, lenders, driving for dollars, probate sales, auction sales, craigslist, oh the list is exhaustive.