2) Are there any circumstances in which tenants cannot sue the landlord?

Your individual facts, circumstances, goals, and exit strategy for this business need to be weighed. 

@Jaysen MedhurstI went ahead and contacted the commercial loan officer at my bank and unfortunately because of the virus he said that the bank is not at all interested in multi family.

I live with in Asia so unfortunately I cant do some of the strategies such as house hacking or even be involved with renovations in person.

Common sense tells me this could be a major opportunity but I’m not sure where to even start or what the best move would be given the circumstances. 

Keep working to find opportunities with relatively minor short-term risks, and long-term rewards.Obviously this is all just my opinion and I don't know exactly what you're circumstances are, but I hope this helps a little.

Unfortunately, the seller is out of state so I can't do a drive by or knock on the door. 

That statement is the key to the kingdom because you have just invoked the federal law, and change (it's court cases saying this, not me) the "code" to a "what's reasonable in the circumstances." 

Typical Class BRenovation Effort: MediumLooking for Contacts: Investment friendly realtors, Wholesalers experience working with out of the state investors.Local Economy Data :  I saw a post @Jack Bobeck gave few details about looking up neighbourhood data and unfortunately i couldn't find that post.

It's imperative you fix what's driving your score to 500 and then move on and unfortunately, sometimes only time can heal a credit score.