It occurred to me to offer a little more information, in case there are other sellers - or buyers - considering a sale of this type - a lease option.
As I mentioned earlier, it is probably best to just do a one or two year lease, with a provision that the tenant has the first opportunity to purchase, should the landlord decide to sell.
Typically, there was an agent or two involved in setting up the lease, and there should also be a provision/addendum making them part of a subsequent purchase, if and when that happens. The commissions should be set at the beginning of the lease, not at the end.
If the transaction does occur, then the agent(s) help the parties come to agreeable price ( possibly with each party hiring an appraisal, and splitting the difference.) and terms, and they open an escrow.
The agent(s) would get paid at the close of the escrow, just like in a normal transaction.
That is how I see such a transaction being a triple win - for the buyer, the seller, and the agent(s).