Broker vs Banker vs Navy Federal Credit Union

[XxRaVeNxX1]

Looking at pursuing a mortgage next year, and I have a few questions. 

I'm honestly ignorant for what the responsibilities of what a mortgage broker  or mortgage banker entails. 

Is a mortgage broker/banker a back up, in case that person's bank denies them?

What incentives are there towards going this route instead of my bank? I'm honestly eyeing that Navy Federal 100% financing option. Helps with not having a deposit.

And they don't help you look for a home like a realtor either correct, just help with the loan?

[Anonymous]

It is my understanding that a broker shops your info to find a loan /lender that fits your profile but the broker does not do any lending/funding themselves,  while the mortgage banker is the person that can originate and  fund their own loans.