They had a window air conditioner running, and the wall gas heater about 5 feet away was also running. 

Tenant units have fire standard doors to the hallway, but if they're propped open - the fire would not be contained.It's up to me to get an air conditioner if I want to be cooler, according to the landlord, but I regularly prop open my door, just like my neighbors do, in order to stay cool.  

An example: we had a young couple who were undergrad students, and we went in there one day to fix something, and found the air conditioner and the heater both running, like mad, each trying to outdo the other.  

Mainly that snake, screwdrivers to remove dead air conditioners, replacing fluorescent lights and that kind of thing. 

Windows units are about as efficient as any other air conditioner as long as they are sized correctly.Personally, I'd buy a few window units and say "Merry Christmas".

What will probably happen, as it did for me, is they will start seeing things that need to be fixed - as they start thinking in terms of "At this new rent amount, shouldn't I have better.....fill in the blank....floors, microwave, air conditioner, whatever."

Of course this is all relative to your climate, maybe air conditioner is a better example in Houston, but you get the point.

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. 

But, as unlikely as fires are, I couldn't live with myself if a tenant died because they couldn't escape out the window:https://www.amazon.com/BLACK-DECKER-BPACT08WT-Portable-Conditioner/dp/B01DLPUWL2/ref=sr_1_1?

Same for your air conditioners - If she doesn't like how you set it up then have her hire a handyman. 6.