I have a back door of a rental unit that has a large glass section (as seen below); and I wonder if I am potentially liable on either side if...1) Someone just breaks the glass, reaches in, easily unlocks the deadbolt from the other side, opens the door, walks in - and cleans out the place...2) Or to prevent this, I put a deadbolt on the door that is keyed on both sides, but then there's a fire and the door cannot be opened for escape without a key!

If you are attempting to rehab into a conventional loan backed by Fannie Mae/Freddie Mac then they have policies in place that prevent you from refinancing as quickly as you can turn them.

If there any 90 or 180 day rule that prevents the sale of a flipped home to a buyer trying to get an FHA or conventional loan ?

I had a team in place ready to tackle this property to prevent any further damage once residents were allowed to return.

I was just trying to help a fellow wholesaler and help him prevent himself from getting into a bad deal that he can't escape from.

Paint on stair treads and floors shall be protected with a durable cover or coating that will prevent abrasion of the painted surfaces.

Assuming you have everything well documented, I do not see anything above that would prevent me from engaging in an exchange. 

My current full-time job prevents me from making many of these functions but Wednesday's are actually pretty flexible for me. 

Of course there is further due diligence and budget adjustments to be made to get your final offer amount but the 70% rule prevents you from wasting your time on something that's not a deal.

The relationship had gone bad between the tenants so the first issue I had was Unit A locking their gate to prevent Unit B's lawn guy from cutting the grass.