If there is a deed transfer involved with the first sale and you take it back you need to hold it at least 12 months to qualify again for capital gains taxes vs regular income (less than 12 months) of ownership!
Instead of doing a straight owner financing, do a Contract for Deed instead. Doing it this way the deed remains in your name and held in escrow until the buyer pays the entire amount owed. Only then does the deed change hands. If there is a default, you still foreclose and the deed is handed back to you.
On a CFD, even though the buyer does not have the deed, he is treated as legal owner of the property and therefore has the responsibility to act like the owner not as a tenant. You are treated as the mortgagee.