On the one hand, safety is paramount.

Update: We have requested a mutual release of contract due to fears for my and my children’s safety since I am the property manager and complete most small repairs myself having my child with me. 

It is reasonable to expect it is coming from another unity, but even if the tenants appear to be clean people they might leave food out all the time.  

If the smoke smell is bad, you should probably wash everything down first, clean the carpets, and then use the ozone generator.These work great on odors from pets, food, or smoke, but it sometimes still requires heavy cleaning first.

They will look at your expenses- college tuition , insurance, food, car, gas, etc to see if you qualify for a mortgage.Also- one option is to get added to your paretns credit card if they have had it s along time with good credit- this will boost your score. 

There was food on plates left around the living room, fly strips hanging from the kitchen light, fruit snacks on the carpet, and the toilets/showers looked like they had not been cleaned in 6+ months. 

What are food ways to start?

Just like food, water, cars, gas, etc. etc. 

If you're looking for additional safety, you could even split some of it to be invested into conservatively underwritten debt, so that if things go badly you can foreclose and recover some or all of your principal.

In class D or C- there are issues beyond just safety.