I'm in escrow on a duplex, my credit score is high 750+, I'm a W2 employee, and I plan on keeping this duplex for more than 10 years.

Quotes vary based on credit scores, points and other factors.The lower rates haven't quite had a foothold in the market yet, meaning active buyers don't have much competition...yet. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

What's the lowest credit score you will allow?

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.

There's plenty of lenders out there that have incredible reviews so might be worth looking around for sanity check

Develop incredible savings habits.

But then it got extremely old and the environment felt incredibly cold.Gray makes everything feel too dark and it doesn't invite people when they are looking for a place to live. 

I currently manage several properties and own a restaurant, which has been an incredible journey in itself.I'm relatively new to property management and real estate investing, and I'm always looking to expand my knowledge and network with like-minded individuals.

Neither one will help their ability to purchase a home or increase credit score unless you are reporting.