I'd look into the possibility of installing heat pumps with electric heating elements for very cold days(one per unit, hopefully, in the units which currently have electric heat) these can be installed in the window much like typical air conditioners and they will function as air conditioners in the summer- some can be installed through the wall.

Also includes all appliances except clothes washer & dryer on both sides as well as air conditioners/furnace as you'd expect. 

Don't forget about the condensation drain from the air conditioner.2.  

The apt I'm in do not have no good ventilation and I can't afford to utilize the air conditioner and can't afford to buy fans like I would need like 2 more fans in order to help the rooms circulate good cool air. 

If I am reading your numbers correctly you are saying that you are cash flowing $876 annually for a $53,000 investment plus your time, risks and unknown expenses e.g. loss due to vacancy, cleaning after a tenant destroys the property, painting, carpets, utilities when it is vacant, new water heater, furnace, air conditioner, leak in the roof, broken or leaking drain pipe, sewer, water pipe, gas leak, or replace or repair leaking faucets, broken screens, repairing locks, trash removal, city sewer use fees and a lot more. 

We took photos, made videos, and were told that they generally do not pay for electronics like TV's, electronic ice makers, and Air Conditioners since it is hard to prove who did the damage or when it was done.

'The air conditioner isn't quite keeping up still. 

When was the water heater put in, the furnace, the air conditioner, the toilets and tub.

But after we had tenants whose various dogs ate my porch swing, the plug off a window air conditioner (haven't a clue why the dog didn't fry himself on that one), dug holes in carpets down to the subfloor, ate the bottom off a closet door, chewed open a door and got under the house in the summer heat to stay cool and crushed a duct pipe and (in one case) were kept under the house so I got to clean feces and urine out from under there on my hands and knees....we rethought our  idea of the need for a pet fee.Gail

Almost all tenants use window air conditioner units.