Can anyone tell me how this might effect my personal credit.

Are you doing full background and credit checks on new tenants?

If they are the best you can do is pay enough that they can come up with the rest and don't completely destroy their credit. 

This might still be a lot for applicants in a C-class neighborhood, but it will be much less work for both of you if they can do it online (again, assuming they have access to a computer and a debit or credit card).

I run my own credit reports with the information provided on the application. 

Pricing for the lower credit scores is higher for obvious reasons.

This is also product and market-driven so there is no "one size fits all" way of doing it. 

I heard credit unions but haven’t yet verified.

Fannie Mae , Freddie Mac , etc. know your credit score and own it .

I think there are two things that are at work here: 1) Investors over estimate how quickly they will get a property operating profitably and therefore don't plan accordingly 2) Turnkey Companies oversell their product and don't manage investor expectations appropriately by explaining item #1 to them.