They specialize in rentals which is nice. 

Pretty tough to get a B home in a nice neighborhood to meet the 2% rule. 

At a bare bones minimum, the letter confirms the start/end dates of the lease, monthly rent, paid-through date, absence of any prepaid rent other than the current month, and security deposit amount.Better, it will include statements there are no unresolved claims or disputes or repair issues with the current landlord, and no verbal or written side agreements.Better yet, it will include a copy of the tenant's lease, and a confirmation the lease is a true and correct copy with no amendments.

I have not yet written a book on this topic.

Would I need a license for that with wholesale or could I be written as a researcher/ consultant fee in the underwriting?

Even wholesaling or flipping requires contracts, and you're not old enough to sign.There are a lot of young people looking to start, and it would be nice to hear more of your story and how they could follow your process.

Of course, easier said then done, and evictions and issues/extra expenses pop up, but if you keep the long term vision, it tends to build on itself quite nicely.

These GPs have a great interest in keeping their potential LPs (marks) ignorant so they will be protecting those interest mob style (dealing with rats).

Now I am wearing the other shoe and it’s nice.

I live in a tent by the river with a nice little otter,  and don't even own a shirt.