In SubTo, the bigger risk is on the seller.

Our whole job is to broker deals between buyers and sellers.

In the event that a seller was to owner finance a property to a buyer without a SSN, is there a market for the Note to be sold to a note buyer?  

With a budget of $300K-$400K, you could potentially find single-family homes or small multi-units in those areas.I'd recommend researching rental demand near universities like Duke or NC State or even checking out neighborhoods with strong job growth near tech hubs.

So we would have to get a loan, pay off the seller and transfer title and then wait the seasoning period before doing a refi unless there is a bank out there that will treat it as a refi off the bat

A property is worth what a willing seller will take from a willing buyer.Is it possible to buy a property in San Diego low enough to get 1% from it, yes.

Rental demand in our market is off-the-chart; the shortage of properties continues to hit historical lows year-over-year.

Do I only draft a cash-for-keys agreement after they've accepted the notion of it or just drop-off the proposal/demand?

The BEST contractors are in high demand, so are picky about doing bids and taking on jobs.

The high end rental properties can be a different animal than your run of the mill $2,500 month rental both in terms of upkeep and demand.