Motion sensor security lights outside, and a cheap wireless security system is also a good choice.

Consider wireless and cellular security.

I wouldn't even bother to insulate if electric heat, put on a wireless or landline thermostat and tell renters to turn on on their drive up and have a nice wood stove.

But I also know that wireless signal can degrade causing poor picture resolution.I personally like all of the points especially numbers 2, 4 and 5.I can't see an issue with running security cameras in common areas, parking lots or corridors.

you need to investigate, because the rules for a 4 unit (considered residential) and the 5 unit (considered commercial) in many jurisdictions in WI you must have a sprinkler system in the 5 unit, some places require it in 3 or more units, as well as hard wired interconnected smoke and CO detectors, you may be able to get away with the wireless inter connected units, but check with the local fire inspector. 

It's most likely a wireless router, so it doesn't matter where the router is placed as long as its within close proximity (50'-100') of her devices.

Most wireless thermostats and control devices use protocols such as Zigbee or zWave for communication and not 802.11 (WiFi) which is a power pig.  

For example, my lease has the following clause in it:NEIGHBORHOOD CONDITIONS: Tenant is advised to satisfy him or herself as to neighborhood or area conditions, including schools, proximity and adequacy of law enforcement, crime statistics, proximity of registered felons or offenders, fire protection, other governmental services, availability, adequacy and cost of any speed-wired, wireless internet connections or other telecommunications or other technology services and installations, proximity to commercial, industrial or agricultural activities, existing and proposed transportation, construction and development that may affect noise, view, or traffic, airport noise, noise or odor from any source, wild and domestic animals, other nuisances, hazards, or circumstances, cemeteries, facilities and condition of common areas, conditions and influences of significance to certain cultures and/or religions, and personal needs, requirements and preferences of Tenant.

They choose to activate it at no cost no subscription it’s built into and the home during the structured wiring phase, as would the utilities of the house.I’m currently renovating my Duplex and plan on installing a surveillance system and wireless access points for Wifi.

It was written in a variety of languages and worked on a variety of devices from wired PCs to wireless bar code and RFID scanners.