With incredibly low supply, what possible indications are there of a housing crash? 

Low minimums getting lower.   

I’m buying into equity and want my monthly payment as low as possible for cash flow.

Looking to establish a banking /lending relationship with a local bank that could possibly do better than 80% LTV on multi family properties and/or some that would have low closing cost on refinancing some multifamily properties. 

You do have to keep in mind that your interest rate will likely be a bit worse (low 5's?)

I always low ball offer properties. 

Or, they have a very low or negative net worth and aren’t concerned with the risk of being sued.

If it's the latter, the online auction sites start the bids low as a teaser in order to get competition and more bids.  

Overall, assuming there is enough demand to meet these numbers and we can buy at these still very depressed prices, it seems like it would be a low floor and low maintenance investment, generate moderate returns for the next 5-10 years, and have very high potential ceiling in the event the area experiences a comeback which many special interests are already working towards.

I've also heard BP podcasts where people bought extremely low priced properties with all cash (under $50,000).