You might do well to specify investors with experience settling an ACV claim.  

If I were to "purchase" a property "subject to" the existing mortgage, could a quit claim deed be used since the seller is in a must sell position, and if so how would you profit from using a quit claim versus signing the contract for the seller to keep the financing in their name fo 3 years?

Quit claim's are easy, but they aren't as solid of a transfer mechanism.  

In other words...if their payment on the house was $1,000...and they could show that they claimed say....$1,000 a month in rental payments...teh lender will consider 70% or in this case $700 towards the payment. 

Currently there is a tenant in one of the units that the current owner claims is the ideal tenant.

Congrats on your first victory!

It sounds very easy, but I think it takes more time, effort and money than some folks claim.  

Now the outside of the wing wall has fell and caused my portion to severly lean, and now they say it's ALL my resposibility, even though they told everyone else that their wall was their wall and my wall is 50/50.My Insurance does not cause pay for structural damage,claim denied.

If the LLC is treated as a sole proprietorship/disregarded entity, then the mortgage interest is claimed on your personal tax return in exactly the same way it would be if the LLC did not exist.  

I have recently found an owner who is willing to quit claim her deeds on 4 properties to me for free.