If reasonable efforts are made by the home flipper to verify contact information and licensing information of contractors (along with disclosing the status of any permits that were or were not obtained) I would think that a legal balance could be found to both compile with the law and protect them at the same time. 

You want to be discerning, trust but verify. 

We verify with Zillow and RentCast.

Verifying recent 2-years of rental history very important!

Some areas may be more flexible (especially unincorporated parts or specific neighborhoods), but it's crucial to verify zoning and licensing rules at the city or county level depending on where you buy.A couple things to consider:Owner-occupancy requirements can vary by municipality.

Verifying recent 2-years of rental history very important!

In our case, what we usually do is ask them to send us a formal signed letter explaining the specific reason why they need to pay their rent in two installments (usually because of how they get paid at work).We also ask for their permission and the contact number of their employer to verify the information.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Verifying recent 2-years of rental history very important!

Guarantors should be individuals and not entities (LLCs or corps), and you should for sure do plenty of background on them (honestly more than the tenant) to verify they have the repayment power should things go sideways.2) This one is tough without a lot more info.