Maybe you get it done easy enough some times, but then other guests won't sign it because ... they're lazy, they're unsure why you're doing something separate from Airbnb, for any number of reasons. 

They can then proceed with a 1031 exchange for their rental properties.I understand their concern about the 180-day timeline.

If you aren't getting a real deal on it then why would you buy it? 

Do you raise money from investors to then front the loans?

The unit SF is one component of its size, but then we will sometimes add exclusive use common areas  as well as a pro-rated allocation of the common area.

If the keys she gave you work, then don't worry about it especially if they were changed to keep a hostile ex out. 

I work in Potomac, MD, and would like to buy a condo or apt that I can easily commute and live in, and then eventually rent out, and then buy another. 

Then look at your options. 

I know there's seller finance and "B" lender that are good for the short term, but if a balloon payment is due say in 5 years, there's no guarantee that my DTI would be in a better place then I'd be stuck without funding. 

If you want a legitimate preapproval then you should be doing a tri-merge "hard" pull.