Yesterday I texted her and told her that she needs to find another place and have an accepted application by the end of July.

I currently use TenantCloud for my property management software and I am able to direct all electronic rent payments to their specific property checking accounts automatically.

She left before final walkout and of course did not leave a forwarding address but I do have her name , SSN and date of birth from her rental application.

That being the case, you'll want to make sure that any accounting software that you invest time and effort into will be able to generate those statements.

Most sensible people will take the cost averaging, while the ones always living on the edge will opt for the higher in-season surcharge; that might help you make a decision between two tenants if you include it as a question on the application. 

Did they provide a point of contact in the rental application? 

I use software that syndicates my rentals to almost 50 different sites (not Zillow).

DEFAULT: If rent or any other sum due Landlord is unpaid; if there is default in compliance with any term of this Lease; if the Premises is abandoned, deserted or vacated by Tenant; or if the Landlord is otherwise entitled under the law, then Landlord will have the right to terminate this Lease in accordance with any applicable statute or ordinance.

If you buy lists make sure they flag do not call numbers so that you limit your contact to snail mail only.Email is pretty ineffective as it will usually get automatically moved by email software into a spam folder and you won't even get their eyeballs.If you have appetite to throw rehab into the mix (either flip or BRRRR) you can add Driving for Dollars. 

The other applicants may have lied to you because they want to gain an edge.