At that time we could renovate the ground floor apartment and potentially turn it into (2) apartments for a total of (5).My questions come down to how do we deal with the existing 40k mortgage, whether we can make it work so her parents aren't paying much in rent, if anything at all, and whether or not we set up any legal entity, like a trust to help the legal situation of paying off her sister down the road. 

Palak,Many online tools like RentSavvy, Avail, Turbotenant, RentRedi, Apartment.com help you do this process. 

You can run other campaigns like Display or YouTube that are more about generating awareness, but specifically for PPC you want to measure leads.

sounds like someone got a nasty gram.. we see this with the syndicators that are called out then threaten the investor who called them out.. or anyone else companing about a service only to have the company either threaten or tell them if you take this down or retract we will give you your money back.. kind of like landlords lying about how great their dead beat tenant is to just get them to move on to the next landlord. 

Then what happens is the lender reports your payment history to the credit bureaus and each time hereafter if you ask for another loan and the lender pulls your credit then they are going to see your payment history and whether you made your loan payments or not which will likely influence whether or not they lend you money. 

You've left that part out.This is what dealing with Class C & D tenants is like!

Is it doable - yes but you will need to go to a lender who probably uses their own funds vs. an instituational lender as they will not like 2nd position nor the low amount.

Sounds like you're doing just fine Ryan!

They may look at 10-15 rentals and if applying ahead is required they might be spending a full months rent on applications and not like any of the places. 4.

Screw her and the scum like her!