PML and HML are two different types of loans/lending programs.

If you are going to call realtors, call them, introduce yourself, tell them you want to send them some information on loan programs that may help them increase business.

They are selling programs and they are telling you that you can do it if you only had the right guidance.

Any recommendations on best way to obtain a commercial mortgage similar to B2R programs?

I'm not sure if the new RRIO program covers this on the inspection, but I do know they look for illegal rental units (which the ADU would likely be considered if you don't live on property).  

As I'm looking to house hack and would love to take advantage of loan programs for first time home owners.

I've definitely seen the land academy system as well as Seth and Marks programs.

Depending on your municipality, you may need to get a certificate of occupancy to rent your property to someone (or face fines).  

I know Ohio, I have found banks that offer less than 15% down for 2-4 units with smaller local banks or different programs like OHFA.

Rates will be a solid amount higher on this program and you will also have to pay points to acquire it.