Real estate is highly regulated and orgs in control may be overthrown, but it will not happen overnight.   

Also I assume it's each city/county is different in terms of regulations but I'm asking as a whole. 

Maybe it has a database of rules and regulations from EVERY county in the country.

Or is that kind of thing stipulated entirely in the existing lease, with no overarching regulation?

It's only on gain and its either 6% or 9% http://www.tax.ri.gov/regulations/other/nrw91-01.php

Does anyone have experience dealing with an HOA with breed specific regulations?

Given that the new Dodd-Frank regulations are absurdly long - I wanted to check and see if anyone is aware of seller financing limitations from the buyer side. 

The pros far outweigh the cons, which include:Safer living & health conditions for tenantsA peace of mind for you as owner & for tenantsWhich can then in turn directly or indirectly, depending on your perspective & outcome, reduce vacany rates Don't forget the other pros;Lead contractors will make a fortuneMore regulation is always betterThe government knows bestThe list you provided above is fluff.  

Unfortunately, there are so many rules and regulations around disclosure that it's not worth it to them to talk to you even if they could eliminate their foreclosure timeline by entertaining a short sale or settlement.

Step one is learn the state landlord tenant regulations before even considering placing a property under contract.