I live in the country, have a video system , for perimeter recording, and a alarm system on my house with panic buttons.  

I'm fire rating the division between units plus adding interconnected smoke detectors and fire alarm!

I have digital locks on my doors and SimpliSafe alarm systems for remote showings. 

I want to see if anyone has used pool alarms or door alarms that work well for guests in your STR.  

We use Ring cameras and alarms because the professional service is really inexpensive. 

You as a landlord of a MF that exhibits the characteristics 1 - 3 listed above, have all the levers you need to pull.Regarding thief, if the property is large enough to make efforts worthwhile, then use best practices to prevent thief.

I asked her if she could afford $25, and she said no, that she understands about the increase, but would have to move.Maybe she was bluffing, but I decided to let her stay at the same rent for another year. 2 weeks ago, she asks if she can install an alarm system at her own expense.

Check though, to see if it can be substituted with a monitored fire alarm system.  

I don't see mold or anything to alarming.

I am alarmed because the settlement attorney handling the sale suggested that I negotiate this amount with HOA and that he has seen others negotiate this amount.