Not sure how an app would automate these types of notices.

Electronic signatures are free using many free apps on the phones. 

Either cell or landline or both if available.

This is my first month house hacking, so I'll download an app to keep better records for the future.

That covers the Do Not Call List and includes texting to those who have not given you permission.If you read that Wikipedia article, there's a case where a group of debt collector companies was fined $75.5M for making automated dialer calls to consumer cell phones.I'd find a different way to reach out to that home owner - assuming that you actually want to work with her. 

I also started using their application process, which doesn't supplant mine but does streamline it, and Zillow's credit app service isn't that much difference from Transunion, which saves me a step in the process.

If they like it, then they complete the credit pull ($35) to complete the app.

The app sends them a one time code 15 minutes before the showing, and the code lasts for 45 minutes. 

County records - each has seemed different even within the same state, but people at the county level are usually helpful directing you where to look.Parlay - an overlay program that works with Google earth (may give owner's name or parcel info to look up)App - Deal Machine.  

I do use CreditKarma and a few other credit apps and it appears everything has been paid.