Bitter Old Man is putting on a clinic, and that isn't meant as a slight to the OP at all! Great stuff!

OP- if you do sort out leasing, you could put the current owners feet to the fire on his leasing activity. One way is to put the agreed value of the leases he says is in the works into an escrow. If the leases close, then he can collect the remainder of the purchase price. If they don't, you are protected and won't end up paying 1.7% cap.