If you can't get the residents out that are not paying, then nothing will help.I would hire an attorney that deals strictly with evictions and start issuing eviction notices to anyone who has broken the laws of their lease.

Check state law because some states require you give them additional time. 

I've been trained in title searching by a law firm, so its been ingrained. 

Sac has always been a place I’ve at least thought about, but I think what worries me a little bit is the more tenant friendly laws in CA.

Running a foul of all kinds of local zoning laws is just the beginning.

Depending upon the local laws, it may be possible that any similar property could be a STR just by a few clicks of buttons to post it online.  

There has never been a standard commission of course (anti-trust laws), but now it is a very different time than it was the last few years!

Your irresistible offer appears to not have turned out so well either by your own admission and my advice is to help you and others reading this about the importance of knowing how and what to have in your contracts, how to properly vet buyers BEFORE you bring them a deal, etc. your situation is a great learning lesson for others and for yourself if you are willing to learn from your own mistakes.As to the assignment being legal or not, I am not 100% knowledgeable on NC laws, however, I have had several experienced investors tell me North C has similar laws regarding this process as does CA, FL, etc.

I think there may be some condo rules/by-laws that prohibit this (that when a unit is purchased it needs to be owner occupied first and a for a certain amount of time before renting).

Hard to tell from here, but your prices seem very high, although I do understand that "emergency" service during the high heat season will cost dearly...As LL, appliances, including HVAC that you have provided in working order, you need to repair or replace as needed unless local law AND your Rental Agreement state otherwise, obvious misuse/abuse excepted.