MLS can be a viable source.

Check Zillow, Zumper, Apartments.com, REALTOR.com, Craigslist, newspaper, facebook, and other sources.

In order to find the best deals, you would either need to have specialized knowledge to spot things others missed or rely on a curated source to find your deals for you before they hit the market.

They'd source these services, I'd pay for them..These charges are usually included in the closing costs of a conventional loan, so again, this sounds legit thus far. 

I wouldn’t use list source or propstream for anything over 4 units.  

Ideally you'd want to work with  a mortgage broker that can source numerous lenders for best pricing and service.

You know the food always sucks, the walk-in is always poorly organized, the boss always has blind spots.

Food for thought to any landlord who wishes all their minority tenants where white; you should only invest in white communities and over the long run believe me, it will help to to avoid all kinds of negative situations that will directly come for you. 

There are expenses and repairs that you'll want to check into and keep track of, and if you're home is still your primary residence it may also be a source of stress as well.

@Jason BrownYou can source for private Money Investors to fund your deals, but they usually would require you to have a skin in the deal.