From the fact sheet it's not clear to me if I would be able to evict both tenants or just one of them because it says you can take possession of only one dwelling unit and I am not sure if each of the studio rooms counts as a separate dwelling unit?

We do co-living for the main stream. 

If it was me...I'd check with zoning to find out how many dwelling units I could build, and I'd find what the requirements are for those units (type of house, height and setback restrictions, etc.).Then I'd find out what local builders think the cost to construct would be - just get a cost estimate per square foot for 2 or 3 different levels of finish.

We should also never have a revenue stream and make money off a tenant's security deposit.

If you are unable or unwilling to do so we may elect to terminate the lease and request a return of our deposit--which we offered in a good faith agreement that we would be presented with a habitable dwelling--and our prorated rent.

Are there some of the data aggregation sites such at Deal Machine or Prop Stream that have this? 

As Nate highlighted, we are proud to have a strong base of repeat clients and a steady stream of referrals.

If you pay cash, you don't have a payment, but effectively you are giving up an income stream if the cash had been in a bond or ETF and earning you either interest or appreciation. 

So I say, I say “Wait a minute… How come REI supports income streams so much better than Stock / Bond portfolios if it has the same return as stocks?”

Deposits from the tenant.Security deposits from the tenant in residential dwelling units shall be deposited in a trust account with a licensed and federally insured depository institution lawfully doing business in this State or the landlord may, at his option, furnish a bond from an insurance company licensed to do business in North Carolina.