I think I could do a business internet plan and setup a wireless system to provide accounts to everyone (I used to work in IT so this wouldn't be hard for me).

Can I tell her to go buy a wireless doorbell to use?

If you have a window that faces your porch you could install a wireless security camera that faces out your window and records as long as it doesn't face directly into someone else's unit.

There are ones now that are cheap, wireless, portable, and work over a cellular network to notify you/police.

Luke, i have separate zones for each unit, each zone ( unit) is controlled by a Honeywell wireless thermostat, Honeywell has a site that you can register and control them from. the front door lock i only have on one property, a SFH, i have not had to use it to let anyone in because my property manager takes care of that, but the feedback from the students and my own daughter, who lived there for 2 years, was that they prefer the keypad to get in the door, as a matter of fact she just bought her first home and that was the first thing she had me do was put in a keypad lock.

Wireless" is your cell phone.My business runs on VoIP (Ring Central) connected to my Cable System's network.  

However, to solve the internet problem I did think about just getting a hotspot device through my wireless company.All in all, I like the concept of the Arlo Cam.

Most people are going to use and prefer a wireless setup.  

The example is in the early and mid-2000s the infrastructure (smartphones and fast wireless connections) didn't exist for companies like Uber & Lyft to exist.

Another option is a video system like Arlo Pro Go is an option (uses wireless vs. wifi).