Alternatively, if your goal is strictly to find cashflow from day 1 (especially if you're coming in with a modest downpayment amount), then I would advise to focus in outer areas. 

If you're considering a significant investment in smart locks, I strongly recommend exploring alternative options that prioritize both convenience and reliability.

I am at a point where I have reached a ceiling with my primary lender and need to find alternative lenders to work with.

I checked out neighborhoodscout.com but I am wondering what good competitors are out there, and if there are any free (or lower cost) alternatives.

Alternatively, if you're able to put a good chunk down payment on a property and the rent(s) cover your mortgage + expenses + a touch more, in an area that you like and know will appreciate, that's pretty nice as well. 

Are there alternative/better financing options for this plan? 

If you are only making $600 a year - you can easily call that negative cash flow - because the first repair you have to make will probably eat that amount up.I would encourage you to compare whatever deal you are looking at to alternative uses of your money as to investments.  

$50k is not enough to make alternative financing work because even at an embarrassing interest rate the investor will only make a few thousand - not enough to justify the time, document prep, risk assessment etc.I'd suggest that you get a realtor to put up the money, take a mortgage plus a few points of the selling price.

Alternatively, should I consider purchasing several single-family homes?

Your closing attorney should be able to explain your options if your real estate agent can’t offer alternatives.