I would be surprised if there weren't notices given to both the defaulting End Buyer (You're in default, you must close by X date or we're forfeiting your deposit) as well as the escrow agent (Buyer defaulted, see contract Earnest Money paragraph regarding release) prior to that actually occurring.

The date you are able to take depreciation is when the property is ready for renting (i.e. advertising for rent or obtaining a certificate of occupancy).

Not to mention, they probably won't want to admit it if a building they manage is in really bad condition.If you're serious about buying you should first talk to fellow investors and define your buy box.

If they were part time and weren't up to date on training, most probably go away. 

If you can strike a balance with mid-term stays, try setting clear end dates to avoid cutting into your peak-season potential.

How many lots in those neighborhoods sold near that date to establish comps? 

I would try to buy properties starting at a specific date so not large ticket items come up.

Generally, the coverage of the policy will state; “The coverage of this policy shall continue in force as of Date of Policy in favor of an Insured after acquisition of the Title by an Insured or after conveyance by an Insured, but only so long as the Insured retains an estate or interest in the Land, or holds an obligation secured by a purchase money Mortgage given by a purchaser from the Insured, or only so long as the Insured shall have liability by reason of warranties in any transfer or conveyance of the Title.”

I would keep the deposit unless I am able to rebook the dates and then I would only make her pay the difference for any unbooked nights. 

Especially filling in the dates on the Full Focus planner.