We even had a serious "bite" that almost moved in earlier this month, but didn't sign the lease.So my question is, since we are about to enter the worst time to get people to move (holidays).

First, you should have a iron clad signed agreement with your property manager for everything.  

The property basis will determine your depreciation expense - one of the most important tax advantages of a buy and hold investor.

(not so important but if they only require 15% down on a single family home that is usually a good sign that you are working with a flexible lender) Can I change title to my LLC?

It could just a joist issue which isn't an expensive fix or something to worry about.Check the ceiling for brown spots as sign of a current or prior leaking room.Window units in house means there is an HVAC issue no matter the reason given by the owner. 

When touring an investment property, what is one thing you look out for that if you see it you immediately WALK AWAY? 

does anyone what factors are used in determining the "class of house" when purchasing property? 

certificate of occupancy, I had to pay for all new exit signs while I was in contract.

I own another house, it was a live in flip, I bought it when I was 20 years old and my father co-signed because of my lack of credit. 

Draw it up in writing and have A & B sign it.