For example, I mention that every adult must pay a $30 application fee, pass my credit/criminal background, make a combined income of 3x the rent, and whether or not the property accepts pets.

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

I pulled out my old amortization book and the lowest rate in the books was 6%  ..

The reason is that we have a relationship with a regional bank that will provide financing and which if we limit leverage to 50% will (1) charge interest at their lowest commercial rate fixed for 20 years with no balloon, (2) charge 0 origination points and no “junk” fees and(3) allow us to sell the property with either a sub to or a wrap loan without increasing the interest rate - in other words no due on sale clause.  

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

The upside is, even with a personal guarantee, the mortgage will not show on your personal credit report.Lastly, in both, while LLCs do offer a level of protection, which is certainly valuable, they also require more work.  

Or perhaps have them pay an extra $50 a month, and then credit them if they overpaid at the end of the year?

I've heard more lenders having issues lately with this "dual layer", even though the standard family trust and its individual settlors are usually the same for liability, credit, and tax purposes. 

Do I understand the interest rates and terms for the home equity line of credit?

Still close by but much more friendly tenant/landlord laws, property taxes are 4th lowest in the Nation, strong appreciation, job growth, population growth, etc.