(Like RC Wiley) The money losing warranties offered by utility companies.

Since you're open to markets beyond NYC, you might want to connect with local investor meetups or REI groups in those areas to build relationships with agents, wholesalers, and lenders who understand the nuances of each market.If you're looking to break out of analysis paralysis, maybe start by narrowing down one or two target markets and running numbers on actual deals.

Quote from @Red Smith: Sheriff Sales are conducted by counties, so each county will have its own individual rule set for how the auction is conducted.

I think you should start by understanding what it is your investors want out of the deal, analyze how the returns compare to traditional investments, and then see where you fit into this deal. 

If you have access to someone who is ready to trust you with their asset, do right by the owner and go for it!

Pay it off and then buy a new primary and turn your current home in to a rental.

You should find out what percentage of the rent is being paid by S8 and by the tenant.Tenants have to sign the rent increase and some won't because they don't want their payment portion increasing.It's also highly unlikely a S8 office will approve the huge increase from $797 to $1300.- BTW: the $1300 includes all utilities being paid by the landlord.

I'm surprised by some of the responses here about how people like VRBO more than AirBNB.

Do you or most landlords comply with the city ordinance to get their properties inspected & registered by the city?

I am with Suncoast currently.Remember: cheaper doesn't mean you'll make more money.Start by going to www.narpm.org to search their directory of managers.