Realistically I believe this means that if you use a service on-time payments will help the tenant with credit scores but late payments won't hurt as they can opt out if they start to make late payments. 

The few lenders I've reached out to in my area (local banks, credit unions, etc.) are only working with primary residence for Helocs or Cash Out refi.

:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

DSCR loans are based off of down payment, credit score and either actual or market rents so it helps to supercharge an investor's real estate goals and net worth.

I have around 700 credit score.

The other option I would consider is regional credit unions that hold onto mortgages/loans and don't sell them to the secondary market - they are "portfolio lenders" and have the ability to be more flexible with their terms.

I have been working with a credit union to get a HELOC to allow me to tap my equity to buy additional real estate.

:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

Is there a bank or credit union that offer a loan for it?

Run the numbers, check for cleaners and handy people availability, see what you can find to outfit the place locally, etc etc.You can, even today, still score a deal and do well with a STR.